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Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diode - Oval - Red Lens
Optronics

Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diode - Oval - Red Lens

Part Number: STL78RB
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$17.16
Retail:$30.67
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7-9/16" x 3-5/16" Oval. 3-Function, waterproof LED light acts as brake, tail, and turn signal. Durable polycarbonate housing and lens. Surface mount with built-in flange - hardware not included. 3-Wire design. Great Prices for the best trailer lights from Optronics. Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diode - Oval - Red Lens part number STL78RB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Optronics Trailer Lights - STL78RB

Highlights

  • One Light, 3 Functions: Acts as stop, turn, and tail light so you get full signaling in one unit.
  • Reliable In Any Weather: Sonically sealed waterproof housing keeps water from damaging LEDs.
  • Fewer Replacements Needed: 10 super LEDs draw less power and last longer than bulbs.
  • Simple Surface Mount: Built-in flange with 7" x 2-3/4" bolt pattern installs flat, no cutout needed.
  • Low Power Draw: Uses only 0.243A on stop/turn and 0.046A on tail for efficient operation.
  • Road Legal: DOT approved red lens keeps your trailer compliant and visible.

Features to know about

Brighter Lighting Without the Bulb Hassle: 10-Diode LED System

If you’re done with dim bulbs or replacing filaments, this 7-9/16" x 3-5/16" oval LED light is a definite step up. It uses 10 super-bright LEDs that handle stop, turn, and tail functions in one sealed unit. With a power draw of just 0.243 amps for stop/turn and 0.046 amps for tail at 12.8V, it shines bright while keeping current demand way down. The result is clean, reliable light every time you hit the brakes or flip your turn signal—no bulb changes needed.

Keeping Water Out Where Others Fail: Fully Sealed, Waterproof Design

Water damage is one of the fastest ways to kill a light, but not this one. The housing and red polycarbonate lens are sonically sealed into a single waterproof piece. That means no moisture sneaks in to fog the lens or corrode the diodes. Whether you’re on wet roads or backing into the water, the light stays clear, bright, and protected.

Quick Mounting That Fits Flush: Surface-Mount Flange Setup

No need to cut big holes or fight with odd brackets. This flange-mount light installs flat against any surface using four mounting holes spaced 7" apart horizontally and 2-3/4" vertically (center to center). Just line up your spots, bolt it on, and you’re set. The low-profile 3/4" thick body keeps it tucked in tight so it won’t snag or catch on anything.

Surface-mount Optronics LED trailer tail light shown installed flat against a trailer surface.

Simple Wiring That Just Works: Three-Wire Hookup

The wiring layout couldn’t be easier. Red handles turn signal and brake, black runs the tail circuit, and white is ground. The design makes it easy to adapt to almost any trailer wiring layout without special connectors or adapters. Once wired in, you’ve got dependable lighting that meets DOT standards and keeps your rig visible from every angle.

Specs

Dimensions

  • Overall dimensions: 7-9/16" long x 3-5/16" tall x 3/4" thick
  • Distance between mounting holes (center to center): 7" long x 2-3/4" tall

Technical diagram of Optronics STL78RB oval LED trailer tail light showing overall dimensions and mounting hole spacing.

  • Overall dimensions: 7-9/16" long x 3-5/16" tall x 3/4" thick
  • Distance between mounting holes (center to center): 7" long x 2-3/4" tall

Electrical Specifications

  • Diodes: 10
  • Power draw at 12.8V: Stop/turn: 0.243 amps; Tail: 0.046 amps

Warranty

  • Lifetime warranty on LEDs

STL78RB Sealed, 6-1/2" Oval LED Trailer Stop, Turn and Tail Light, Flange Mount, 10 Super Diode 0.243V/0.046A

Alternate part number: STL-78RB





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
7-9/16" x 3-5/16" Oval. 3-Function, waterproof LED light acts as brake, tail, and turn signal. Durable polycarbonate housing and lens. Surface mount with built-in flange - hardware not included. 3-Wire design.

by:

Was exactly what I needed: Surface mount, holes exactly 7 inches apart for the sides. Needed it for a replacement on our 2018 Grand Design 399TH Momentum.



by:

On time as promised.



by:

Very nice product. Installation on my very old utility trailer was easy. I like the slim design compared with my old chunky incandescent lights which were easy to break and not as bright as these LEDs.



by:

Quality product well made and designed,
Reasonably
priced. Best suited for my application. Also purchased the red reflector snap ring that covers the mounting flange and screws.



by:

Exactly what I ordered and expected with fast shipping!



by:

Worked great as a replacement for OEM that was no longer available for RV. I also replaced the back side marker lights so the front and back matched.
Pat C did a great job in completing my order with substitution for out of stock resistor.



by:

I had a hitch carrier in the garage and wanted to add brake lights/turn signals. Since there were no mounting locations for lights, I needed a surface mount option. These fit the bill. They work great and were easy to wire with the harness I bought.



by:

Tail light was just the model I needed. Hooked it up, works perfect. Good communication between etrailer and me on tracking my order. Will definitely use them again.



by:

Excellent trailer lights at a reasonable price. Very fast delivery.



by:

Good product. Horizontal bolt hole spacing is the same as a license plate so it conveniently mounts anywhere a license plate would. The LEDs are bright enough as auxiliary running/turn/brake lights and the wiring is simple. The mounting flange is not very strong plastic so you have to be careful not to crank down on the mounting bolts. There is no hardware included and no gasket for the backside, which is a bummer. Otherwise, a very nice product.



by:

Wired them in and they light up, blink, and do everything else they're supposed to do. Let me also mention that they are BRIGHT at night. Loading the boat onto the trailer at dusk/after dark they're almost blinding when the pickup driver steps on the brakes. Lol



by:

I bought one of theses lights last year to replace one that had some of the LED's going out. Same manufacturer and same part number. The new light uses a different type of LED (square LED). The old style used an LED that looks more like a small bulb. I have 4 of these on the back of my 5th wheel trailer. The other three started going bad so I just replaced them as well. I have other LED lights inside the trailer that use the same type of LED as the new tail lights. I've had those lights for 6 years with no problems. . I suspect these new lights will last much longer with the new type of LED.



by:

Now that I'm finishing up on my Teardrop Trailer I've got these lights installed, along with a LED tag holder, and LED marker lights. I had also bought the fenders from etrailer they look great, and I get a lot of comments how good all these parts look. Oh and the prices are better then any place I could find.......Thanks etrailer



by:

Part was exactly what we needed. Shipping was quick - Thanks!



by:

This has been a very good product. The light was easy to order and install. I have not had a problem with it working properly and I expect it to keep working for years to come.

Chris profile picture

Chris

3/27/2026

After a year the light is still working even with the trailer sitting out in all kinds of weather. This is a very good product.

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

3/27/2026

@Chris Glad the light is still shining bright for you, Chris!


by:

The 10-diode tail lights were well made, bright, and easy to install. We also ordered and installed the matching reflector rings, which were also easy to install, look great, and give added safety features.

Kathryn profile picture

Kathryn

10/14/2022

Lights are sleek and a perfect replacement. Still doing an excellent jodb! Would purchase again if needed.



by:

After one of the the incandescent trilights the factory installed on my trailer burnt out I discovered they where sealed and the bulbs could not be replaced,
So I purchased two of these and discovered they are ery nice lights and unlike incandescent lights they don't screw up the turn signal flash rate.

I am now in the process of rebuilding a trailer mounted generator and just ordered 2 more of them for that trailer and I also bought LED marker lights from the same manufacturer.

If you need new or replacement taillights or marker lights LED's are the way to go, long lasting, nice and bright and in my opinion they way they instantly light up get more attention from drivers behind me possibly reducing the chances of getting my trailer rear ended by a inattentive driver.



by:

Perfect replacement for the til lights on my trailer. Thank you etrailer for having what I needed, and the detailed information to know it was the right part to order.



by:

The Optronics LED lights fit perfectly on my 2021 Keystone Outback. Installation was easy. It took longer to remove the old sealant.



by:

Replacing original tailights on 2018 ca mper.

Scott C. profile picture

Scott C.

5/17/2026

After 1 year, lights have worked great! Still bright as when I installed them. No condensation behind the lens or other problems. I would buy again!

Lazer S. profile picture
Etrailer Expert

Lazer S.

5/18/2026

@ScottC Nice! Glad to hear they are still working well for you! Were the lights you replaced fogging up or just old and worn out?


by:

The lights were easy to install. They are bright lights, very visible in the sunlight.
We installed these on our older dump trailer, replacing the old lights.
They fit perfect, and look and work great.



by:

Great product. An exact copy of what I had installed on my enclosed trailer. It was an easy install with color matching wires. Great quality, easy install and an excellent price point. Can’t go wrong here folks.



by:

I just installed the new trailer lights on our Sundowner horse trailer. The lights are of good quality and replaced the original lights no fabrication needed. The wiring matched up well with the existing wiring.



by:

Perfect fit. Installation took longer than it should due to very poor previous repair performed at the dealer. Glad I chose, at 73 swf, to do rhe work myself. The first time I have had fully functional tail lights since buying in 2022. Woo hoo.



by:

Light was the same size as previous one on EZ Loader boat trailer. Easy to install and very bright. Original one made it 10 years and had moisture inside causing most of the LEDs to stop working.

Matt G. profile picture

Matt G.

6/30/2025

Submersible light is still working properly. Good product for the price.


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See what our Experts say about this Optronics Trailer Lights

  • Adding Additional Taillights to 6 by 10 Utility Trailer
    I don't have a wiring diagram specifically suited to what you're wanting to do, but I can certainly explain how to wire the additional lights. If you're wanting to add the # STL78RB lamps, the red wire taps into the turn signal/brake circuit, the black wire connects to the running lamp circuit and the white wire grounds to the trailer frame. You may tap into the existing trailer taillight circuits. Since these are LED taillights, the additional voltage draw will be minimal. For your existing...
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  • Installation of Optronics Sealed, 6-1/2 Inch Oval LED Trailer Stop, Turn, and Tail Light
    Thank you for your purchase from etrailer.com! The Optronics Sealed, 6-1/2 Inch Oval LED Trailer Stop, Turn, and Taillight # STL78RB that you purchased will need to be hardwire installed on your trailer. You will want to connect the light to your trailer's wiring by function. You can use a circuit tester, like # PTW2993, to determine the functions of your trailer wiring. The white wire on the light will need to be grounded. I recommend running the light ground back to the main trailer...
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    Hey Andy! To add a third brake light to your trailer you will need the following: -Curt 2-to-3 Tail Light Converter for Towed Vehicles w/ Incandescent Tail Lights # C56196 -Load Resistor Kit for LED Turn Signals # DI34ZR The converter will isolate the brake signal so your light only activates with the brakes, not the turn signals. Since this is designed for incandescent lights you will also need to add in the resistors so it works properly. Some customers have had success by pulling...
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    The lights we offer that are closest to the size you mentioned that we carry is part # STL78RB. These lights measure 7-9/16 long when you also include the mounting flange, x 3-5/16 inches wide, x 3/4 inch deep. This light has 10 LEDs and is a waterproof assembly. The mounting holes for this light are spaced 7 inches center-to-center, and 2-3/4 inches for the width. This light has 3 wires, red for the brake and turn signal, black for the tail light, and white is for ground.
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  • Is There a Gasket for the Optronics LED Trailer Tail Light STL78RB?
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  • Is Optronics LED Trailer Tail Light a Direct Replacement for 2018 Casita Lights
    Hi Michael; lights can vary from model to model even within the same year so I can't say for sure if this is an exact replacement for your 2018 Casita. The best thing you can do is measure to see if the size matches. The # STL78RB is 7-9/16" long x 3-5/16" tall x 3/4" thick. If this matches the shape and dimensions you currently have you're all set. I went ahead and attached a picture below showing the dimensions, including the distance between mounting holes. Let me know if you need anything...
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  • Replacement 6-1/2" Oval Lights for a Heartland Utility Trailer
    Hey Adam, thanks for reaching out! For surface mount lights you need the Optronics LED Trailer Tail Light # STL78RB, but if by flush mount you mean recessed, then you need the Optronics Fleet LED Trailer Tail Lights w/ Grommets # TLL12RK. Both kits come with 6-1/2" oval tail lights. I'm not sure what exact style came on your Heartland utility trailer, but either of these will be the same size as your 6-1/2" lights. Please let me know if you have any questions about these!
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  • Troubleshooting Malfunctioning Trailer Lamps on 2015 Lakota Horse trailer
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  • Are Load Resistors Required When Installing LED Lights on a Trailer
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