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  1. Trailer Cargo Organizers
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  8. Mobile Business/Office
  9. Recreation
Locking Floor Mounted Storage Box for Enclosed Trailers - 19" x 29" x 7-1/4"

Locking Floor Mounted Storage Box for Enclosed Trailers - 19" x 29" x 7-1/4"

Item # M387FR
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Our Price: $321.69
Trailer Cargo Organizers
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Shipping Weight: 46 lbs
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Locking storage box mounts in the floor of your enclosed trailer and gives you space to store your hauling essentials without losing floor space. Galvanized steel box with black powder coat lid resists rust and corrosion. Lowest Prices for the best trailer cargo organizers from M-3 and Associates. Locking Floor Mounted Storage Box for Enclosed Trailers - 19" x 29" x 7-1/4" part number M387FR can be ordered online at or call 1-833-496-1390 for expert service.
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M-3 and Associates Trailer Cargo Organizers - M387FR

  • Floor Storage
  • Locking Storage Box
  • Contracting
  • Hobby Space
  • Landscaping
  • Mobile Business/Office
  • Recreation
  • Drilling Required
  • M-3 and Associates
  • 29 Inch Long
  • 21 Inch Wide

Locking storage box mounts in the floor of your enclosed trailer and gives you space to store your hauling essentials without losing floor space. Galvanized steel box with black powder coat lid resists rust and corrosion.


  • Locking, floor-mounted box gives you secure storage space without losing floor space
  • Large latch allows for easy opening
  • Durable galvanized steel construction
  • Black powder coat resists rust and corrosion
  • Made in the USA


  • Dimensions: 19" wide x 29" long x 7-1/4" deep
  • Weight: 48 lbs
  • 1-Year limited warranty

9500489 M-3 In-Floor Locking Storage Box for Enclosed Trailers - 19" x 29" x 7-1/4"

Video of Locking Floor Mounted Storage Box for Enclosed Trailers - 19" x 29" x 7-1/4"

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Review of M-3 and Associates Trailer Cargo Organizers - Locking Floor Storage Box - M387FR

Michael: Hi there, I'm Michael with Today, we're going to take a quick look at the locking floor mounted storage box for your enclosed trailers. This floor mounted box is going to give you extra storage space without losing any of your floor space. It's going to be great for storing your tie-down straps or to keep your personal gear secure while you're out working. It does have a 50 pound internal weight capacity, so you can put anything up to 50 pounds inside there, and it's going to keep it nice and secure. And unlike some of your other storage options, rather than taking up space to put a shelf in your trailer or something like that, where you're going to be losing space that could be filled with your vehicle or other materials, this is actually going to add space to your trailer.It's going to give you a nice place to store things out of the way, and it is going to mount flush to your floor, so if you wanted to, you can put carpet over top of it, keep it kind of like a hidden compartment for you.

It is a nice looking compartment, so even if you don't cover it up, it's going to add to the look of your trailer. I think it's just going to be a nice option for you to keep you items stored.It does have this large latch here at the front. It's going to make it easy to pull open. You can see, we do have these gas struts on both sides. These are going to help make sure that the lid stays open.

It's not going to close on its own. Even if you had a big gust of wind or something, you're not going to have to worry about it slamming down on your hand. Those gas struts help keep it secured.On the inside we do have these bars here that the lid will sit on when it's closed. That's going to make sure that it is nice and sturdy so we can drive over the top of the box. It does have a 1000 pound weight capacity, so obviously if you're driving over it with a car, only one tire is going to be on it, or one wheel is going to be on it at a time.

As long as your car is under 4,000 pounds, it should hold up well, and can still give you the usable space to drive over and stuff. This does have a nice durable galvanized steel construction, and you can see it does have a black powder coat finish. So again, it's going to look really nice, hold up well, you're not going to have to worry about rust, corrosion, those sorts of things.Overall, very nice box here. I do want to give you a few dimensions to make sure that this is going to work for your application, so I'll jump to the overhead view again here. This does have a total width of right about 27 and three quarters of an inch.

That is the box itself. If we're counting the frame here, that's looking at about 30 and three quarters of an inch in total width. Then for our depth, for the box, we're at right about 18 and seven eighths of an inch, for our frame we say about 21 and five eights of an inch. If we open this back up again. If I'm measuring the depth here, how tall this is, how much you can fit inside here, a couple of things to consider. From the bottom up to the lid, you're only going to have, this portion here that is that full height, cause you have your locking mechanism here in the middle, and then you've got those bars on the perimeter there. Your overall is going to be right about seven and an eighth of an inch.But for those few areas where it's going to sit below there, I can't really measure this with the box closed. It's about an inch and a half from here, so take away that measurement I just gave you, but then with these arms here, it is about six and three eighths of an inch tall. So keep that in mind, make sure that any gear that you're going to want to put in here will fit with that. But if you're just using it for your tie-down straps, things like that, it should fit in there very easily, so you shouldn't need to worry at all about that.This does have a variety of mounting location options, so you want to consider that when you're installing this. If you are going to put tie-down straps or something like that in there, it might be better to have it towards the rear of your trailer so it's easier to access after you've driven your ATV or motorcycle or whatever that you are hauling into your trailer, you can still pull the latch and open it from the back. It's right there at the back so it's easy to access. But it is going to stick down about seven inches below your floor, so keep that in mind for your clearance, those sort of things. If clearance is a concern of yours, you may want to put it closer to the wheel well so it gives you a greater clearance there. But just things to consider.This is going to be a nice sturdy box with that steel construction, black powder coat finish. It weighs about 48 pounds, so it is manageable for one person to load it up. It should be pretty easy to get it installed. They include instructions, silicone sealant, mounting screws, and of course the keys to get it unlocked and locked so that you can easily just put that in and we'll lock it into place, so if you are out doing some landscape work or something like that, you want to throw your wallet and phone inside the box and make sure that it doesn't walk away. You have that option. It's going to be nice and secure.This is made here in the US and so you can trust it's made to the high quality standards that we've come to know and trust for products that are made here in the USA. And it does come with a one-year limited warranty. So if you we're to have any problems within that first year, you could give us a call. We'd help you out with that. But overall, I think you're going to be very pleased with this box. Again, just giving you more storage options for your enclosed trailer.One thing I do want to point out is that this is for enclosed trailers because these arms here or the support bars, there's no seal to it, so it wouldn't be protected from the elements. They do include the silicone sealant so that you can make sure that it's sealed between the cutout and your trailer, make sure that nothing gets in that way, but this is for the enclosed trailers. Just something to keep in mind for you there. But that's going to complete our look for today. Again, I'm Michael with Thanks for watching..


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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Mike S
Written by:
Mike S
Employee Michael B
Installed by:
Michael B

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