bing tracking image
  1. Trailer Lights
  2. Optronics
  3. Tail Lights
  4. Round
  5. LED Light
  6. Red
Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diodes - Round - Red Lens
Optronics

Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diodes - Round - Red Lens

Part Number: STL42RB
In Stock
$18.74
Trailer Lights
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.
By submitting this form, you understand and agree to our Terms of Sale, Website Terms of Use and Privacy Policy.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

5-1/2" Diameter round. Waterproof trailer light serves 3 functions: stop, turn, and tail. Durable polycarbonate lens and housing. Mounts on trailer with built-in flange. Accepts standard 3-prong plug. Great Prices for the best trailer lights from Optronics. Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diodes - Round - Red Lens part number STL42RB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (2198)
  • Q & A (0)
  • Photos

Optronics Trailer Lights - STL42RB

Highlights

  • One Light, 3 Functions: Provides stop, turn, and tail signals in one 5-1/2" round housing.
  • Reliable In Any Weather: Sonically sealed lens and housing keep water out for submersible use.
  • Fewer Replacements Needed: 10 LEDs last up to 50 times longer than incandescent bulbs.
  • Easy Wiring Connection: Uses industry-standard 3-prong plug for quick, clean installation.
  • Low Power Draw: Uses just 0.413 amps for stop/turn and 0.26 amps for tail at 12.8 V.
  • Road Legal Fit: DOT compliant for safe, visible, and legal trailer lighting.

Features to know about

Brighter and More Efficient Lighting: 10-Diode LED Design

Upgrading to LED is all about better visibility and low power draw, and this light nails both. The Optronics LED Trailer Tail Light uses ten LEDs that shine brighter than incandescent bulbs while drawing less current—just 0.413 amps for stop/turn and 0.26 amps for tail at 12.8V. You get a clean, even red light through the polycarbonate lens with no filaments to break and no bulbs to swap out. It’s built to last about 50 times longer than conventional lights, so you can spend more time towing and less time troubleshooting burnt-out bulbs.

No More Water Worries: Sonically Sealed, Submersible Construction

Water intrusion can ruin lights fast, but not this one. The housing and lens are sonically sealed into a single waterproof unit that’s fully submersible. That means moisture stays out, even during boat launches or heavy rain. The sealed design protects the diodes and internal circuit board from corrosion, keeping your lighting system reliable mile after mile.

Straightforward Installations: Built-In Flange Mounting

When it’s time to replace or upgrade, this light makes it simple. The built-in flange mounts directly on your trailer using three holes spaced 4-1/4" center-to-center. It fits a standard 4-1/2" round cutout, so you won’t have to rework your existing setup. Just connect it with a standard 3-prong plug like the A45PB or A47PB (sold separately), and you’re good to go.

Durable Construction That Lasts: Polycarbonate Lens and Housing

Rough roads and constant vibration can take a toll on your gear, but the tough polycarbonate construction keeps this light holding strong. The lens and housing resist cracks and wear, maintaining clarity and protection around the LEDs. At 5-1/2" in diameter and 1-15/16" thick, it offers a solid, flush-mounted presence that looks clean and professional while standing up to the elements.

Reliable Safety Compliance: DOT Approved 3-Function Light

Safety isn’t negotiable when you’re on the road. This round LED tail light handles all three functions—stop, turn, and tail—and meets DOT standards for visibility and performance. With bright output, rugged sealing, and efficient operation, it’s a dependable way to keep your trailer visible and compliant wherever you tow.

Specs

Dimensions

  • Overall diameter: 5-1/2"
  • Thickness: 1-15/16"
  • Distance between mounting holes (center on center): 4-1/4"
  • Required hole size for installation: 4-1/2" round hole

Technical diagram of Optronics STL42 Series 4-inch round red LED trailer tail light with mounting flange, showing dimensions and mounting hole layout.

Electrical

  • Voltage: 12.8V
  • Power draw (Stop/Turn): 0.413 amps
  • Power draw (Tail): 0.26 amps
  • Diodes: 10

Compatibility

  • Accepts standard 3-prong plug: A45PB and A47PB (both sold separately)
  • Manufacturer cross reference: Truck Lite # 44326R, Grote # 53292, Peterson # M418R-2

Warranty

  • LEDs: Lifetime warranty

STL42RB Optronics LED Trailer Tail Light - Stop, Turn, Tail - Waterproof - 10 Diodes - Round - Red Lens

Alternate part number: STL-42RB





Customer Satisfaction Score:

Ratings & Reviews

4.8

2198 reviews
5 Stars
(1897)
4 Stars
(205)
3 Stars
(46)
2 Stars
(19)
1 Star
(31)
Review sort icon
5-1/2" Diameter round. Waterproof trailer light serves 3 functions: stop, turn, and tail. Durable polycarbonate lens and housing. Mounts on trailer with built-in flange. Accepts standard 3-prong plug.

by:

These LED tail lights are exactly what I have been looking for to renovate a trailer with recessed lights. I was excited to find them available from the etrailer company. Placing the order was easy, the company notified me when the order shipped, and the lights were delivered in a VERY TIMELY fashion!! This company has earned a 5 star rating, as well!

John G. profile picture

John G.

4/30/2018

Lights continue to function well and they still look great!! Fantastic quality!



by:

Perfect fit and exact replacement on my Ranger Boat trailer.
Excellent service and arrived sooner than expected.



by:

These lights worked out great. good price too!
EZ install.

David profile picture

David

7/10/2020

Still working great!!



by:

Just as advertised! Work perfect and look great! Fast shipping as well!



by:

Perfect fit, wiring as described! Perfect upgrade for our 60s Sears Tent Trailer



by:

Exact match to my ranger trail original tail lights



by:

Try to label the leads, but then again why do anything that requires effort on etrailers part



by:

These are exact replacements for my 2009 RangerTrail trailer. Fit perfectly.



by:

Just as advertised. * Delivery date was missed by 3 days



by:

Thanks... the light is perfect and at a great price. The other place wanted $26.00 for the same light and you charged much less. I highly recommend etrailer.com for parts.



by:

Installed nicely and very bright!



by:

Product is perfect and quick shipping.



by:

It would have better to have video choice appear on pre-order review about cleaning all electrical connections and verifying no tow vehicle fuses needed INSTEAD of purchasing LED replacement taillight not needed.



by:

100 times better than the original lights I had with traditional bulbs. With the LEDs you can see them even better during the day. Which is nice to know that people can see me at all hours of the day.



by:

Fantastic replacement for old white backup lights.



by:

Great product, fair pricing, and super fast shipping.



by:

Very fast at getting shipped out.



by:

Great lights, very bright and visible day and night, much much better than the factory bulb light. I have recommended them to our friends who have RV's
Thanks etrailer



by:

I put these LED lights on my 1967 Scotty. They have a nice clean look, and show up so much better than the originals. The wiring process, with the plug in connections, was easy!



by:

Lights worked well for my trailer repair



by:

After ordering July 11th and a roundtrip from Missouri to L.A. to Keswick Ontario, Canada we received the shipment July 25th. Tailights fit my 2006 Ranger trailer perfectly. Thanks to Paul for tracking my shipment when it didn't arrive on the originally scheduled delivery date and keeping me updated.



by:

Used these to replace old lights on my horse trailer. Installation was easy and they are very bright. I had issues with a connector on my first order, but the second was just fine. I also had issues with one being dim, but found out it was my trailer plug. Once it was replaced, it was great! Would use these on another trailer if needed.



by:

Perfect fit and plug was perfect as well on my 2009 Ranger Trail trailer!



by:

Exact fit and an excellent replacement for the lights on my 2006 Ranger Boat trailer.



by:

Perfect fit and exact replacement for my 2008 Ranger Z21 trailer. Great price and fast shipping. Totally satisfied!!!


25
25

See what our Experts say about this Optronics Trailer Lights

  • Replacement Tail Light For Forest River Georgetown XL RV
    I'd be happy to assist you. It sounds like you need the Sealed, Flush Mount Tall Rectangle LED Trailer Stop, Turn and Tail Light, Grommet and Plug, 12 Diode # STL34RB but most of the pictures I see have round tail lights like the Sealed, 4" Round, LED Stop/Turn/Tail light, 21 Diode - Red # STL55RB. If this is not the correct part, then send me a photo with the measurements of the light and we will get you what you need. The numbers and letters that are actually printed on the light are...
    view full answer...
    Image 1 for Image 2 for Image 3 for
  • How to Connect the # STL42RB Tail Lights to a 1958 Trailer with 2 Wire Lighting System
    The 4 inch Round Sealed LED Stop, Turn or Tail Light, item # STL42RB, uses a 3 wire pig tail, item # A47PB or # A45PB, to connect to your existing trailer wiring. The plug on the pigtail plugs into the back of the tail light and is then hard wired to your trailer wiring. It sounds as if your original tail lights were grounded to the trailer frame through their mounting studs, so a third wire was not needed. When connecting the 3 wires from the 3 wire pig tail, you will ground the white...
    view full answer...
  • Need Tail Lights And Wiring For 5x7 Utility Trailer
    Hello Greg, thanks for reaching out. Really any stop, turn, taillight could work for that purpose. The Optronics LED Trailer Tail Light # STL42RB will be a great option as long as your have a solid surface to mount to. The mounting holes are 4-1/4" apart on center. To wire them up you will need the Right Angle 3-Wire Pigtail for Optronics Trailer Lights # A47PB. Then to wire the trailer you will just need a 4-way harness like part # A35W42B. This is 35' long so you can cut it down to...
    view full answer...
  • Replacement Taillight for Grote 5273 Trailer Light
    Hey Bob, yes the Optronics trailer taillight part # STL42RB will replace your Grote 5273 but it does not come with a pigtail harness so you will need to provide that separately with the part # A47PB.
    view full answer...
  • Replacement for Round Tail Lights From Superbrightleds
    Hello Britton; the closest thing we have is the Optronics LED Trailer Tail Light # STL42RB. This has the same 5-1/2" overall diameter and requires a 4-1/2" round hole for installation. It also uses the same 3-prong plug you have now. It has less diodes but it is still a bright light. The number of diodes doesn't necessarily mean a light is dimmer or brighter. The one thing I didn't see listed is the distance between the mounting holes. The Optronics light measure 4-1/4" center hole to...
    view full answer...
  • Replacement Taillights, Wiring and 7-Way Connector for Car Hauler
    To fit the round 4-1/2 inch holes on your trailer for the rear brake lights you could use the # STL42RB as this will fit in that hole. For a pigtail harness you would also need # A45PB. For the side clearance lights you would need to enlarge the holes to 3 inch in diameter, use the # A55GB as a grommet and then use # MCL59AB for the lights and # A46PB as a wiring harness. For a replacement 7-way with 8 feet of wire for running new wire everywhere you would want the part # H20046. You...
    view full answer...
    Image 1 for
  • What Size Hole Needs to Be Cut To Install the Sealed 4 inch Diameter Optronics Light STL42RB
    To install the Sealed, 4" Round LED Trailer Stop, Turn and Tail Light, Flange Mount Light # STL42RB that you referenced you will need to drill a 4-1/2 inch hole for the light to fit and the mounting holes will be 4-1/4 inches apart on center. For a pig tail harness you will want the part # A45PB.
    view full answer...
  • Replacement Option For Glo-Brite 9891-88 LED Trailer Tail Light
    We do have an option for you to replace your Glo-Brite 9891-88 LED trailer tail light. Based on my research this is a 4 inch round LED tail light that uses a 3-wire plug and fits in a 5-1/2 inch grommet. We have exactly that with the following light: - Optronics LED Trailer Tail Light # STL42RB This comes with the grommet, which has mounting holes separated on center by 4-1/4 inches, so the only other thing you will need is the 3-wire pigtail, and you can choose from a standard or right...
    view full answer...
  • Replacement Tail Light for 2009 Ranger Boat Trailer
    Sometimes it is possible to replace a broken trailer light with one that uses a different type of installation but since we offer a very wide range of lights you may very well be able to find an exact OEM-style replacement. It sounds like you have a light like # STL42RB which has a 3-hole mounting flange. I linked our main page for trailer tail lights of all shapes and sizes. On the page you can simply click on the filters for light shape, light type (LED or standard bulb), lens color,...
    view full answer...
  • Replacement Lights for 1989 Interstate Box Trailer
    The diameter you are looking for is 4-1/2" on the # STL42RB. This would be the widest part that would fit into the hole on your trailer. We do not have an LED option without the plug but we do have the Peterson # PM425-3. This has the same mounting hole dimensions and is also 4-1/2" at the widest point on the back. If you decide to stick with the Optronics light you will need the # A47PB or # A45PB.
    view full answer...
    Image 1 for Image 2 for
  • Converter Recommendation to Install Combined Taillights on a Flatbed Truck that had Separate Bulbs
    It sounds like you need to convert the separate wiring of your 1991 Nissan truck to a combined setup to work with the Round LED Taillight # STL42RB. For this you will need to get a Roadmaster Brite-Lite Wiring Converter # RM-732. You will run the wires from your vehicle to the right side of the # RM-732 by function, and then from the left side of the box you will run the corresponding left or right turn signal wire to the red wire of the # STL42RB. The tail light circuit will bypass this...
    view full answer...
  • How to Ground a Trailer LED Light that Only has 1 Wire
    If a light has just 1 wire that means that it grounds through its mounting hardware. Be sure to use steel hardware and mount the light to a clean and corrosion free bare metal surface. If there isn't a steel surface where you want to mount the light you can place a ring terminal with attached wire between the hardware and mounting surface and attach the other end of the wire to a steel surface.
    view full answer...
  • Do Trailer Lights Sometimes Ground Through Mounting Hardware
    There are quite a few trailer light assemblies that use the mounting bracket as the ground. This works because the mounting brackets typically get attached to metal surfaces that touch the trailer frame which is where the ground strap of the trailer wiring harness connects. You can run a jumper wire from the mounting hardware to the main ground wire of the trailer if you wanted to as well.
    view full answer...
  • Flush Mount Stop Turn and Tail Lights for a 1982 13 Foot Scamp Travel Trailer
    I did a bit of research on your trailer and the reflect-o-lite light that you mentioned. It looks as if they are surface mount lights that are 6-7/8 inch diameter. For a replacement you could use the 7 inch round Transit LED Stop/Side Marker/Tail Light, # STL90RB, to have a somewhat original appearance, with an upgraded LED light. You could also use a surface mount like the I recommend the Dual LED Trailer Tail Light - Stop, Turn, Tail, Backup - Red and Clear Lens # CE86FR by Command electronics,...
    view full answer...
  • Can Utility Lights in Trailer Run Off Running Light Circuit Through a Switch on an Aluminum Trailer
    Yes, you can run the switch power wire to a clearance light but the trailer would have to be connected to the vehicle with the running lights on for the interior lights to have power. Aluminum does not offer the best ground so if the lights do not work you may have to run a jumper ground wire to a steel component or the main trailer connector ground. I would try it first to see if there is any problem with grounding to the aluminum surface. A fuse is not needed though you could add one...
    view full answer...
  • What is the Power Draw of Optronics LED 4 Inch Round Trailer Tail Light # STL42RB
    Because tail light # STL42RB has more than one function it has more than one amperage draw rating. Brake lights and turn signals draw more power so that will be the higher draw at 0.413 amps. Running lights use less power and would be the 0.26 amps. If you have the running lights on and then step on the brake, the brake light overrides the tail light. If you have the brakes on (with or without the running lights on) the turn signal will override the brake light on that side. So the most...
    view full answer...
  • Replacement Tail Light Assembly For 2005 Airstream Trailer
    We offer several lights and may have just what you are looking for that will fit your 2005 Airstream. Thank you for the photo of your lights. You will want to take a measurement to be sure you get a light that will match the housing you are installing it in. if you remove a light you may be able to get the part number of the light assembly. If you cannot find the part number you can measure the opening and mounting holes to make sure we get a light that will work. The light assembly...
    view full answer...
    Image 1 for Image 2 for
  • Will Each LED Taillight Need to Be Grounded Separately on Trailer
    When it comes to wiring an LED taillight like the Sealed 4" Round LED Trailer Stop, Turn and Tail Light # STL42RB with Pigtail Harness, # A45PB, the red wire is for stop and turn, the black for running lights, and the white wire will need to be attached to a clean and corrosion free bare metal surface on the trailer. As for a clearance light having two wires like the Rectangular LED Trailer Clearance and Side Marker Light, # MCL32AB, you will ground the white wire and connect the black...
    view full answer...
  • Round LED Trailer Tail Lights to Replace Peterson Incandescent Lights
    Three inches is small for a tail light. There aren't even any incandescent stop, tail, and turn lights as small as 3 inches. It looks like to get what you want you will need to got to a 4 inch light. If you like the Peterson lights and need a flush mount that mounts in a grommet you could use # 435800. It does use the plug-in style connector but you would still hardwire all of the wires, including the grounds, to the trailer. This light includes the grommet and pigtail. I have included...
    view full answer...
  • Availability of 3-Prong Pigtail Plugs with Load Resistors
    The Optronics Round LED Trailer Stop, Turn and Tail Light # STL42RB does use a 3-prong plug for electrical connection. We offer right-angle 10-inch pigtail plug # A47PB and straight pigtail plug # A45PB. Neither of these includes a load resistor, which can be required on some wiring systems to mimic the higher electrical resistance of standard incandescent lights. Some turn signals will hyper-flash when used with LED lights because the wiring does not "see" the load from the super-high-efficiency...
    view full answer...
  • Sealing Up Around a Trailer Tail Light Using Tail Light # STL42RB On an Airstream Trailer
    You could use a gasket maker like # LT37464. You would just need to put a small bead of the gasket maker around the outer most flange on tail light # STL42RB. I have included a picture to show you what this would look like. You could also use silicone # 0160297 around the light and at the mounting holes after you have installed it.
    view full answer...
    Image 1 for
  • Troubleshooting Running Lights Circuit on a Travel Trailer Tail Light Harness
    Since you have tested the 4-Way connector on your vehicle and it is working properly, it leads me to believe that the wiring of the lights is incorrect. You will want to make sure that the fuse for the running lights on the vehicle is not blown. It sounds to me like the lights you have only have two wires coming out of the back for wiring to the trailer connectors wiring. If this is the case then the red wire will connect to the yellow (left) and green (right) wires on the trailer lights....
    view full answer...
  • Replacement LED Trailer Light to Reduce Power Draw
    The Optronics LED Trailer Light # STL42RB is not what I could call an exact replacement for the # ST40RB but for all purposes it will be what you're looking for. The # STL42RB is 1/8 inches larger in diameter and 3/8 inches deeper so at the most you may need to do a little filing to the opening for the light in your trailer to install it. The mounting flange is metal. There is also a Stainless Steel Trim Ring # A5TRSSB available. It does not include a gasket, however If you would prefer...
    view full answer...
  • Does Sealed, 4" Round LED Trailer Tail Light STL42RB Also have Reflectors
    Trailer tail light # STL42RB has reflective properties but I recommend # STL43RBX. The mounting ring around this light is a reflective lens rather than just a black ring like with # STL42RB. I also recommend wiring harness # A47PB to plug into the back of the light.
    view full answer...


< Previous



Do you have a question about this Trailer Light?


Info for this part was:

Employee Robert G
Expert Research:
Robert G
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee John H
Expert Research:
John H
Employee Adam R
Expert Research:
Adam R
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Kathleen M
Video by:
Kathleen M
Employee Jacob H
Video by:
Jacob H
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Brian T
Updated by:
Brian T
Employee Hannah L
Updated by:
Hannah L
Employee Cole B
Installed by:
Cole B
Employee Andrew S
Installed by:
Andrew S
Employee Shane H
Installed by:
Shane H
Employee Chris R
Video Edited:
Chris R

At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.