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  1. Vehicle Suspension
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SumoSprings Solo Custom Helper Springs - Rear Axle

SumoSprings Solo Custom Helper Springs - Rear Axle

Item # SSR-307-40
Our Price: $320.99
You Save: $180.49
Vehicle Suspension

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1,000-lb Capacity. Upgrade your vehicle's rear suspension with these maintenance-free helper springs. Sturdy microcellular urethane springs cushion bumps and help support a heavy load to level your ride and minimize sway. No-drill installation. Great Prices for the best vehicle suspension from SuperSprings Intl. SumoSprings Solo Custom Helper Springs - Rear Axle part number SSR-307-40 can be ordered online at or call 1-800-940-8924 for expert service.
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SuperSprings Intl Vehicle Suspension - SSR-307-40

  • Jounce-Style Springs
  • Rear Axle Suspension Enhancement
  • Light Duty
  • SuperSprings Intl

1,000-lb Capacity. Upgrade your vehicle's rear suspension with these maintenance-free helper springs. Sturdy microcellular urethane springs cushion bumps and help support a heavy load to level your ride and minimize sway. No-drill installation.


  • Helper springs upgrade your vehicle's rear suspension for improved driver control and comfort
    • Keep your vehicle level when you're towing or hauling a heavy load
    • Help to absorb bumps and shocks
    • Minimize sway
  • Progressive load control - springs compress according to the weight of your cargo
    • Lighter loads - springs compress easily at first for soft engagement and a less bumpy ride
    • Heavier loads - springs compress by as much as 80 percent for support
  • Springs work independently from each other to compensate for off-center loads and reduce body roll during sharp turns
  • Durable microcellular urethane
    • Works in temperatures from -25 F to 200 F
    • Resists damage caused by oils, road salts, and UV rays
  • Minimal lateral expansion - springs compress vertically instead of to the sides so they aren't easily damaged when operating in tight spaces
  • Maintenance-free - no tubing to run or air pressure to monitor like with air springs
  • Simple, no-drill installation
  • 2 Jounce-style springs included
  • Made in the USA


  • Weight capacity (at 50-percent compression): 1,000 lbs
    • SumoSprings will not increase your vehicle's weight-carrying capacity
  • Limited lifetime warranty
  • 30-Day satisfaction guarantee

Rear Suspension Support

Towing or hauling a heavy load can cause rear sag as your factory suspension compresses under the weight of the load. This means that the rear axle is trying to support not only the extra load but also the weight of your vehicle. And because there is less weight on your front axle, your front tires make less contact with the road, which causes problems with traction, steering, and braking. SumoSprings upgrade your vehicle's factory suspension to level your vehicle, improve driving performance, and keep your ride comfortable.

Installed spring when it is not compressed

SumoSprings provide progressive load control - the more you load them, the stiffer they become. With a lighter load, the springs will compress easily for soft engagement and a less bumpy ride. The closed-cell urethane material allows for smooth contact between the springs and your vehicle. And the springs act like a shock absorber to dampen road vibration.

Installed spring when it is compressed

The springs can also compress by as much as 80 percent to support a heavy rear load and to help your factory suspension bear up under the load. This evens out the weight, which levels your vehicle and ensures that your front tires are making better contact with the road. A level ride means that you have improved driving control, ensures safe headlight aim, and helps to minimize sway. The springs also support your factory suspension, which helps prevent sagging and reduces bottoming out.

The springs work independently from one another to support each side of your vehicle. This action helps to reduce body roll when you make a sharp turn. This also helps compensate for an off-center load.

Durable, Custom-Fit Springs

These microcellular urethane springs are tough. They resist abrasion, oil, salt, and UV rays that can more quickly wear out other springs, and they perform well in temperatures ranging from -25 F to 200 F (-33 C to 93 C).

SumoSprings compress vertically with minimum expansion to the sides, so they won't be damaged by nearby mechanical parts and they fit safely into tighter spots. And unlike air springs, SumoSprings require no maintenance or adjustment.

The helper springs are custom designed to fit your vehicle, and they install easily - no drilling required.

SSR-307-40 SuperSprings Sumo Springs Solo Rear Vehicle Suspension Kit for Trucks

Installation Details SSR-307-40 Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

SumoSprings Solo Custom Helper Springs - Rear Axle - SSR-307-40

Average Customer Rating:  4.7 out of 5 stars   (2171 Customer Reviews)

1,000-lb Capacity. Upgrade your vehicle's rear suspension with these maintenance-free helper springs. Sturdy microcellular urethane springs cushion bumps and help support a heavy load to level your ride and minimize sway. No-drill installation.

Dodge Ram Pickup

I love my Ram, but I would white knuckle it while towing my travel trailer which is 3000 lbs. under my towing capacity. Well, I was skeptical that a $300 part could make a difference in the handling of my truck. But this has made a whole world of difference. No porpoising, minimal sway and NO white knuckles. And when I’m not towing, I don’t even know the springs are there. I highly recommend these helper springs!

Dodge Ram Pickup

2019 Ram Rebel. I followed the advice in the reviews and got the 1000 lb. and didn't use the spacer. Works perfect pulling my 30' Toy Hauler. Hitch weight is 1200 lbs. They take some patience installing them. Some of the nuts are hard to get at. Took about an hour to get them installed.

Mark H.


After a year and 3,000 miles pulling my toy hauler, Im very happy with the performance and ride.

Etrailer Expert

Mike L.


@MarkH Glad to hear that the SumoSprings # SSR-307-40 is still working well for you!


arrived on date at order orination. continue to use UPS they set the standard. suggest to add make/model specific instructions regarding mounting hole, spacer requirerment. I found youtube video(s. Also suggestion to develope mounting to match OEM/Timbren.



performs 100 as described

2021 Dodge Ram Pickup

My 2021 Ram 1500 Laramie would squat when attached to our 6800 lb travel trailer even w/ a weight distribution hitch. I bought the blue SumoSprings, installed them in an hour and a half, and took the truck to the trailer. The squat is completely gone and both my trailer and truck are level. Looks great! Little bit of a change in ride quality w/o the trailer, but nothing too drastic. I would recommend these helper spings/bump stops. As a side note, I did add the 1 inch space before installing them (it comes with the kit).

2020 Ram 1500

etrailer had a great explanation for which spring to get based on how I planned to tow. Ordering and delivery was quick without complication. When I received the box all the parts were there. I own a 2020 Ram Rebel 4x4 with a tow package. I used a couple 4x6 blocks to place under the tire jack and lifted the body via the trailer hitch enough to get the springs into place. The OEM stops came out by hand. The instructions are basic and could have included a better illustration. I started with the passenger side and quickly realized that I needed an open socket wrench. I ended up buying a set because the nuts are difficult to get to. Once I had the 1/2” open socket wrench for the top nuts the job went smoother and much quicker. The passenger side required some manipulation for the bracket to clear the spring and be aligned with the axle stop. The drivers side assembled exactly like the illustration stated. I drove it over my normal curbs and speed bumps and the rear end is harsher than I expected but not noticeably so on the open road. The truck sits ever so slightly on the springs with the spacer in and I expect this to eliminate the sag when I tow. I may consider taking the spacer out if I don’t like the ride. There are two shorter bolts included if this is desired though there is no explanation for this in the instructions.


These went on in an hour. They took the stress off the equalizer bars and made installation and removal of the bars much easier.



They work as promised. They’ve solve issues with towing the trailer.


Sumo springs work well. Fairly easy to install.
The reason for 4 stars instead of 5 is because of the instructions being somewhat confusing.
It says to mount the sumo springs closest to the wheel and “furthest to the back of the truck”.
So does that mean furthest from the back? No! The springs need to seat closest to the back. Pretty frustrating! Better wording could make this a lot clearer, and a picture of after install would make it perfectly clear.

2022 Ram 1500

Excellent product and fast shipping. Had a minor fitment issue, which was quickly sorted out with a phone call. Thanks eTrailer and SuperSprings.

2019 Dodge Ram Pickup

2019 Ram 1500 Big Horn 5th Gen. Easy but tedious install. Couldn't get a socket wrench in, so I had to use a reg 1/2" wrench to tighten all the nuts. I went without the spacers to leave the unloaded ride at stock suspension. left about 1/4" space between sumo springs and axle. Hitched my camper up and suspension sag went from nearly 2" down to less then 1". Didn't have a chance to tow yet, but anticipating less bounce and a more stable ride.



Still very satisfied with the product.


Got them installed shortly after arrival. Process pretty straightforward, but, being arthritic and old, I had it done at a local shop. Bought them to make my little 1/2-ton truck ride more level with the slide-in camper on. Seems to have worked.


sumo Springs work great and easy to install and i don't have to mess with air

2017 Ram 1500

I have not towed my TT with the springs yet so can’t do a 5, yet! Solid 4 so far. Install was easy and simple. Hauled 2 full coolers, 4 bags of deer corn, 6 guns, heavy duty floor jack and clothing for 4 people plus the four of us in the truck. Didn’t ride rough or bounce excessively at all. Will post again after I pull the TT.

2019 Dodge Ram Pickup

On a 2019 Ram 1500 things get tight when trying to get the top brackets on the studs while holding up the Sumo spring. Then to tighten the nuts with the frame, coil springs and brake lines it will take some time to get everything tight. So far the ride is a bit stiff nothing to worry about tho, just hope it helps out on pulling our travel trailer and corrects the drifting I had on the front wheels.

2017 Ram 1500

The installation is fairly easy. There are two extra bolts in the kit incase you want to exclude the one inch spacer. The instruction leaves out this information. The hardest part is tightening the bolts on the unit installed on the left side. The exhaust makes it a little tight. Removing the wheels is a big plus and highly recommended when using jack stands and floor jacks. After installation, I noticed a slightly higher rake in the rear, Headlight aim seemed fine and no noticeable ride difference. I will hook up my trailer next weekend and see if it helps with the ride and leveling of the truck. So far, product meets my expectations.


Had these on for a week now. No spacers and about 3/4” clearance. Nice thing I like is the ride height stays the same with no change to the regular ride quality. Only notice it’s stiffer on a big highway bump but not obtrusive. I would not go with heavier ones on a 1/2 ton truck. I won’t really get to test them until summer when I tow a 8000# boat. In the past with the boat on the hitch the truck sagged and was too springy. These I am sure are going to fix the sag and the springy issues.


Install wasn't hard, just a pain to get to all the little nuts. A ratcheting 13mm wrench (not a socket) would be worth buying.

unloaded ride seems the same, have not yet towed with them.



Still happy with them. Done plenty of towing long and short distances and i have no complaints.

2016 Dodge Ram Pickup

I put these on my motor home and was amazed at the improvement in handling and stability. I switched to to a 35 foot travel trailer which squatted my 1500 Ram.
These Sumo springs reduced the squat to a minimum and and improved the towing stability. A must have if you haul a heavy load.

2015 Ram 1500

The team at Etrailer has great communication and will order with them again.

Dodge Ram Pickup

Still holding up great. If you tow quite a bit like I do ( 40' Travel Trailer 7000 Lbs ) then they're a must. All my notorious RAM sag is eliminated. Highly recommend !


The tech support was superior !

John M.


Working Great


Easy install, function’s as advertised.

2019 Ram 1500 Classic

Easy install, haven’t pulled my trailer yet but seems to be doing it’s job. Btw spacer not needed unless you want a stiffer ride.


Do a great job with a load but still does make the truck ride a bit rougher when empty, overall happy with them.


Wasn't bad to install probably took a hour. No load hauled yet.


Great transaction. Fast delivery.

Show More Reviews

See what our Experts say about this SuperSprings Intl Vehicle Suspension

  • Timbren or SumoSpring Kit for 2022 Ram 1500 Big Horn Crew Cab
    If you value your ride quality at all I would recommend the SumoSprings like the part # SSR-307-47 which has the 1,500 lb capacity. This will give you the support you are wanting without destroying your ride quality which the Timbrens are more known for.
    view full answer...
  • Which SumoSprings Kit for 2020 Ram Rebel 1500
    We have two SumoSpring options that fit your 2020 Ram 1500 Rebel with the tow package. We have the part # SSR-307-47 which can provide up to 1,500 lbs of additional support or we have the # SSR-307-40 which can provide up to 1,000 lbs of support. Since you will be on the higher end of your towing capacity the better option would be the 1,500 lb # SSR-307-47. Unlike other options (Timbren specifically) the SumoSprings aren't nearly as harsh so the higher capacity kit won't make your daily...
    view full answer...
  • Best SumoSprings For 2022 Ram 1500 Towing Camper Trailer
    The best option for SumoSprings for your 2022 Ram 1500 for towing a camper trailer are the 1,500 lb capacity springs, with the correct fit for your truck being the following: - SumoSprings Solo Custom Helper Springs # SSR-307-47 The reason why the # SSR-307-47 are the best for your '22 Ram for towing a camper is because they have enough capacity at 1,500 lbs to give your suspension the support it needs and won't provide a stiff ride like the higher-rated springs can. The 1,000 lb SumoSprings...
    view full answer...
  • Recommended SumoSprings for a 2021 Ram 1500 Pulling a Travel Trailer
    Thanks for the picture! For your 2021 Ram 1500 I recommend the SumoSprings Solo Custom Helper Springs item # SSR-307-47 over an air bag system. These 1,500 lbs capacity springs have a progressive load control. Which means the springs compress according to the weight of your trailer or cargo in the bed. When you are not towing or loaded down you won't notice they are installed. Under a heavy load these springs will compress by as much as 80% to support your suspension and keep your truck...
    view full answer...
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  • Recommended Suspension Enhancement For 2022 Ram 1500 TRX Towing Gooseneck Trailer
    To reduce the squatting you're experience while towing I recommend the SumoSprings Solo Custom Helper Springs # SSR-307-47. These will provide you with additional support and will help keep you level while reducing sway. They also have a minimal impact on unloaded ride quality. They feature progressive load control so the springs compress according to the weight of your cargo. They have a weight capacity of 1,500 lbs and a microcellular urethane construction to hold up to the elements....
    view full answer...
  • SumoSprings Helper Spring Recommendation for 2022 Ram 1500 Classic
    We offer two SumoSprings options for your Ram 1500 Classic. For 1000 lbs of support, use the # SSR-307-40 kit you'd looked at. For up to 1500 lbs of support, use # SSR-307-47. Either kit is compatible with in-bed 5th wheel or gooseneck hitches. If you click the provided link, you can see an install video.
    view full answer...
  • Ride Comfort for SumoSprings When Unloaded
    The SumoSprings Solo Custom Helper Springs item # SSR-307-47 have a 1500 lbs capacity whereas the SumoSprings Solo Custom Helper Springs item # SSR-307-40 have a 1,000 lbs capacity for lighter towing and hauling applications. Both are designed to offer a stable ride when your 2019 Ram 1500 Classic is loaded down or towing a heavy load. The SumoSprings are by far the most ride comfortable jounce style springs available. There would be minimal difference if any at all when unloaded. They...
    view full answer...
  • Custom Helper Springs For A 2019 Ram 1500
    The SumoSprings Solo Custom Helper Springs # SSR-307-47 has a higher weight capacity being at 1,500 pounds and The SumoSprings Springs # SSR-307-40 have a 1,000 weight capacity. The # SSR-307-47 will be your best bet on your 2019 Ram 1500. The sumo springs have a simple, no-drill installation and will work in temperatures from -25 degrees F to 200 degrees F. Using the Sumo Springs will not increase your vehicle's weight-carrying capacity. I attached an installation video link below.
    view full answer...
  • Recommended Solution to Fight Sag When Towing in a 2021 Ram 1500
    The SumoSprings Solo Custom Helper Springs - Rear Axle # SSR-307-47 you were looking at are a really nice solution to help fight the sag you're experiencing and they'll also help with road shock to help smooth out your ride a bit. I really like the SumoSprings compared to an air bag since they're maintenance free and you don't need to add a compressor to get the most out of the system. SumoSprings are progressively load bearing, so they'll get stiffer as more weight is applied on them;...
    view full answer...
  • Recommended Rear Axle Jounce Spring Kit for 2017 Ram 1500 4x4 Quad Cab
    Air bags kits are a better option when your trailer or cargo load varies a lot, especially with an uneven cargo load, but for towing one trailer that is more or less uniformly loaded up each trip I recommend jounce springs. Jounce springs will give you progressive rear axle support when you need it but they will otherwise not affect your ride quality. They also cost less than air bag systems, are much easier to install, and they require no maintenance. Since most of your trailer's 5900-lb...
    view full answer...
  • What Is The Mounting Hardware Of The SumoSprings Solo Custom Helper Springs SSR-307-40 Made Of?
    I reached out to my contact at SuperSprings and the Solo Custom Helper Springs # SSR-307-40 you were looking at for your 2021 Ram 1500 Crew-Cab 4WD include mounting hardware that is made out of standard steel, and is not stainless steel. If you are worried about rust building your best bet would be assembling the spring and then painting the hardware before mounting. I included a video of the # SSR-307-40 for you to take a look at.
    view full answer...
  • Will The SumoSprings Solo Helper Springs # SSR-307-40 Fit 2016 Ram 1500 With Factory Air Suspension
    The SumoSprings Solo Custom Helper Springs # SSR-307-40 can interfere with factory air suspension on your 2016 Ram 1500. Since the factory air suspension is designed to allow the truck to lower or rise while driving the helper springs will not allow it fully lower and may cause the system to have errors. All of the helper spring type systems we have for your Ram are going to be for the spring system.
    view full answer...
  • Which SumoSprings Kit for 2017 Ram 1500 with 4" Lift
    You can use the SumoSprings Solo Custom Helper Springs # SSR-307-40 on your 2017 Ram 1500 with a 4" lift but you may need some spacers to get the maximum performance out of these springs. The total stack size of these springs and mounting hardware is 6-1/2", and they will mount in the spot where your factory bump stops currently sit. In regards to whether or not you'll need a spacer, my tech contact over at SuperSprings recommends measuring from the face of the cup where the factory bump...
    view full answer...
  • Upgraded Bumper Stops For A 2022 Ram 1500
    If you're looking to help the suspension on your 2022 Ram 1500 absorb road shocks better you can for sure install a set of aftermarket jounce bumpers, like the SumoSprings Solo Custom Helper Springs # SSR-307-40. I like these springs over the others because they provide one of the smoothest rides possible and will work great when carrying heavy cargo or towing a larger trailer. The springs have a simple, no-drill installation. If you have any further questions please feel free to reach...
    view full answer...
  • Will the SumoSprings Solo Custom Helper Springs Work w/ Factory Air Suspension on a 2023 Ram 1500?
    Yes, they will. The SumoSprings Solo Custom Helper Springs item # SSR-307-40 are compatible with the factory air suspension on the 2023 Ram 1500's. You'll definitely get some error codes thrown at you on the lower end but there won't be any issues when you've got the ride height set higher. You won't even notice the SumoSprings are there.
    view full answer...
  • Timbrens or SumoSprings Kit for 2020 Ram 1500
    For your 2020 Ram 1500 and how you plan to use your truck the best suspension enhancement is the SumoSprings Solo part # SSR-307-40. This kit is the better balance between ride quality and support than the Timbren you mentioned as well. Timbrens are best for people who mainly use their vehicle for towing or otherwise loaded down and need the support most of the time. Unloaded they are pretty harsh. Whereas the SumoSprings give great support still but they aren't nearly as harsh unloaded.
    view full answer...
  • Can SumoSprings Solo Kit Fit 2011 Dodge Ram 1500 4WD Quad Cab with Coil Springs
    Yes, the SumoSprings Solo kit part # SSR-307-40 is a fit for your 2011 Dodge Ram 1500 4WD that has rear coil springs.
    view full answer...
  • Suspension Enhancement Recommendation for a 2021 Ram 1500 with Off-Road Package
    For your application you need jounce-style suspension enhancement as all of the air bag styles won't be compatible with an off-road version of your 2021 Ram 1500. There are 2 options to choose from and it depends on what you're looking to get out of your SES (suspension enhancement system); the Timbren # TDRTT1500 and the SumoSprings # SSR-307-47. Out of these options I recommend the SumoSprings. They have a lower weight capacity but they are also more forgiving than the Timbrens. The...
    view full answer...
  • Recommended Suspension Upgrade to Stop a Sagging Rear End in a 2021 Ram 1500
    I would be happy to! To keep your rear end from sagging when you're pulling a trailer or hauling a load in your 2021 Ram 1500 bed, I recommend the SumoSprings Solo Custom Helper Springs item # SSR-307-47. These have a 1,500 lbs load leveling capacity. They attach with custom fit mounting brackets and are compatible with both the 2WD and 4WD models. The SumoSprings item # SSR-307-47 work off a system called progressive load control. They only engage when there is weight put on them. These...
    view full answer...
  • Timbrens or SumoSprings For 2021 Ram 1500 Crew Cab For Helping With Sag
    For your 2021 Ram 1500 Crew Cab, between the Timbren Rear Suspension Enhancement System # TDR1500DQ, 1,000 lb capacity SumoSprings Solo Custom Helper Springs # SSR-307-40, and 1,500 lb SumoSprings Solo Custom Helper Springs # SSR-307-47, the option I recommend for your Ram is the latter: - 1,500 lb SumoSprings Solo Custom Helper Springs # SSR-307-47 While neither will completely eliminate sag, the SumoSprings will offer the same quality as the Timbrens in terms of suspension support,...
    view full answer...
  • Suspension Enhancement for 2019 Ram 1500 Classic
    I checked with RAS and they do not offer a fit for the 2019 Ram 1500 Classic at this time. For a suspension enhancement kit that fits your truck that provides support without being overly harsh the SumoSprings kit part # SSR-307-40 would work great.
    view full answer...
  • Suspension Enhancement for 2019 Ram 1500 Classic for Use with Weight Distribution
    Since you are wanting more support to improve ride quality I actually would not recommend an air bag kit as they are notoriously pretty harsh when inflated. They provide great support but when in use the support is not as soft as what "air bag" might imply. So instead the best solution is a SumoSprings # SSR-307-40 which will give you a softer support.
    view full answer...
  • 1,500 lb or 1,000 lb SumoSprings For 2016 Ram 1500 With Weight Distribution
    Thanks for all that info it was definitely helpful, and we can get your 2016 Ram 1500 set up with the right SumoSprings. You are right about the SumoSprings being something that will help your truck, and between the 1,500 lb SumoSprings # SSR-307-47 and 1,000 lb SumoSprings # SSR-307-40, I recommend going with the 1,000 lb option: - SumoSprings Solo Custom Helper Springs # SSR-307-40 The reason for that is you mentioned you already had a weight distribution system, and that you didn't...
    view full answer...
  • SumoSprings Solo Custom Helper Springs for 2022 Ram 1500
    The SumoSprings Solo Custom Helper Springs, # SSR-307-40 are rated at 1,000 lbs. and the # SSR-307-47 are rated at 1,500 lbs. These are a great products and improvements over the factory components however, because you state "...very close to maxing out my payload capacity so I need to make sure I did the most supportive thing possible..." I do not recommend these because they are not the best for your situation. The Air Lift LoadLifter 5000 Ultimate Air Helper Springs with Internal Jounce...
    view full answer...

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Info for this part was:

Employee Leah B
Edited by:
Leah B
Employee Mike L
Expert Research:
Mike L
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Employee Andrew K
Video by:
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Employee John S
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Employee Mary K
Written by:
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Employee Wilson B
Updated by:
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Employee Alex H
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Employee Noah M
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Employee Robert C
Installed by:
Robert C
Employee Jacob H
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Test Fit:
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