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Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Red Lens - Passenger Side

Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Red Lens - Passenger Side

Item # ST20RS
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Optronics 4 Inch Diameter Trailer Lights - ST20RS
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3-7/8" Diameter round. Incandescent trailer light serves 3 functions: stop, turn, and tail light. Screw-on lens. Durable steel housing. Stud mount to trailer with included studs. 2-Wire design. (1) 1157 bulb. Lowest Prices for the best trailer lights from Optronics. Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Red Lens - Passenger Side part number ST20RS can be ordered online at or call 1-833-496-1390 for expert service.
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  • Reviews (41)
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  • Videos (1)
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Optronics Trailer Lights - ST20RS

  • Tail Lights
  • Round
  • Incandescent Light
  • Red
  • 4 Inch Diameter
  • Surface Mount
  • Stop/Turn/Tail
  • Non-Submersible Lights
  • Optronics

3-7/8" Diameter round. Incandescent trailer light serves 3 functions: stop, turn, and tail light. Screw-on lens. Durable steel housing. Stud mount to trailer with included studs. 2-Wire design. (1) 1157 bulb.


  • Incandescent trailer light serves 3 functions
    • Stop, turn, and tail
  • Incandescent bulb is easy to replace
  • Shock-proof socket protects bulb against damage
  • Durable steel housing with screw-on lens
  • Red lens over incandescent bulb
  • Compatible with 12V DC systems
  • Stud mount to trailer with included studs
  • 2-Wire design includes power lead and ground wire
  • DOT compliant


  • Configuration: passenger side
    • Driver side: ST21RS (sold separately)
  • Dimensions: 3-7/8" diameter x 3-1/16" deep
  • Distance between mounting holes (center on center): 2"
  • Bulb type: 1157
  • Power draw at 12.8V:
    • Stop/turn: 2.3 amps
    • Tail: 0.9 amps
  • 3-Year limited warranty

Optronics ST20 Series Surface Mount Tail Light Dimensions

ST20RS Optronics Trailer Tail Light - Stop, Turn, Tail - Surface Mount - Round - Steel Housing - Red Lens - Passenger Side - Right Hand

California residents: click here

Video of Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Red Lens - Passenger Side

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

Video Transcript for Optronics Trailer Lights - Tail Lights - ST20RS Review

Today we'll be reviewing part number ST20RS. This is the Optronics Trailer Light for the passenger side. The round trailer light is going to serve as your brake light, turn signal, and tail light. It's got the red acrylic lens that's simple to replace. It's going to attach with the two included screws. Very easy to change incandescent bulb that's going to offer a bright light.

It's going to sit in a shock-proof socket for a long bulb life. It's also going to feature the black enamel-coated steel housing that's very durable and strong, as well as corrosion resistant. Here on the rear, it's going to have the two lead wires exposed. These are the wires needed to connect your light, and then the unit's going to ground through the mounting hardware. This is a surface mount design so it's going to mount using the two studs on the back of a housing. Those are included.

They simply just slide into the channels and then you can adjust them as needed to best suit your towing application. It is Department of Transportation compliant so it meets FMVSS108 and CMVSS requirements for automotive lighting. Again, this is for the passenger side. If you need one for the driver's side, you can find that here at using part number ST21RS. This is going to give us an overall diameter of 3-7/8" with an overall depth of 3-1/16".

The bulb type is 1157. It's a double filament. Power draw is at 12.8 volts so when using the brake light that's going to be 2.3 amps, turn signal is 2.3 amps, and the tail light is 0.9 amps. Again, the installation is going to use those two studs that are included, and once those are installed they're going to measure 2" center on center apart from one another. We're going to go and connect this to our external power source so that we can see what the light looks like with power running to it and with our overhead lights turned off. So go ahead and make all of our connections.

The red wire's going to be for the tail light function, so we'll get that connected. Then the black wire on the back of the housing is going to be for our stopper 00:01:59 and turn signal. You can see here it sends out a nice, consistent signal. This is going to be the tail light function. It's going to brighten up when we apply the brakes, and it's going to do that same thing when we apply our turn signal. That's going to do it for today's review of part number ST20RS. This is the Optronics Trailer Light for the passenger side of your trailer. .

Customer Reviews

Optronics Trailer Tail Light - Stop, Turn, Tail - Round - Red Lens - Passenger Side - ST20RS

Average Customer Rating:  4.9 out of 5 stars   (41 Customer Reviews)

3-7/8" Diameter round. Incandescent trailer light serves 3 functions: stop, turn, and tail light. Screw-on lens. Durable steel housing. Stud mount to trailer with included studs. 2-Wire design. (1) 1157 bulb.


This light barely blinks like something is wrong with it. Plus it looks like the brake is on for this light. There is no issue with the wiring it is all new. The one for the drivers side works with no issue. This one to say the least was disappointing.

You mentioned that it was not working properly and I wanted to ask to see if the ground had been tested?
-- Etrailer Expert Jenny N - 04/18/2022


These are very nice brake/turn signal lights. They will get installed later on my fj40 and will require very minor modifications to the rear cross beam. Very happy with these high quality lights and for a very reasonable price!


Quick delivery and reasonable delivery fees. Product is just as advertised-good quality for the low price. I used two of them for a homemade sign for the wall above my model railroad. The lights were wired to a switch and then to an alternating flasher and they "wig-wag" flash just like the real thing! Very satisfied with these lights.


I needed to replace a cargo trailer light assembly and checked Lowes, Home Depot, a local marine shop and a trailer supply store with no luck, I did an online search and found the etrailer site. The item was ordered and received in 3 days and was exactly what I needed. This was a very efficient and easy process and will be the first place I refer to for any trailer part needs in the future.


I am very happy with these taillights. I put them on my golf cart and they work great. Highly recommended.


Easy to install, as advertised. Nice and bright and arrived quickly.


Fast shipping and great service


Product Review:I had these type lights on an old Toyota rust-bucket with a wooden bed which still is my most loveable vehicle; can't find these lights locally (N/W NC mountains); found your ad online and hoped these would match those already on the Toy and replace some damaged and rusty; couldn't believe I could get exact replacements, but I sure did; order date March 29 early AM, mailman handed them to me April 31 at 1 PM at my house "in the same year!" They had traveled, according to map, across from the edge of Missouri through the southern edge of Indiana, across the length E-W of Kentucky, SW Virginia to Greensboro, NC, then backtracked on land back to my home via USPS to me. Put them to your ear and you could still hear the Mississippi!!

Give it a big 5 stars!


Just right!


Very nice light and a very good price, I installed two of these lights on a 1971 Toyota Land Cruiser for tail lights

Very good
Jim R - 03/27/2018


Got the tires, wheels, lights, and wiring kit to rebuild an old utility trailer. The website has a wealth of info to help find exactly what was needed. Michelle S. was very helpful (and friendly!) in resolving a delivery question.


My order arrived in good time, well-packaged and complete. The quality of the materials looks to be very good and I can't wait to get them installed on my trailer and bring it back to life.

Etrailer's communication and customer responsiveness is fantstic!


Used them for the tail lights on my golf cart. They work great and have not had any problems with them.

Great Product No Problems
Bob H - 10/12/2017


This light set I bought a year ago are still great and is close to my old light that is enclosed by wrap around guard so it fits perfectly well and works well..


always satisfied with quality and service. returning customer.


Well, the UPS man was NOT happy. He chewed on me for not having my name on the package. I reminded him that I didn't send the package. The address, minus the name, would have gotten to me with no fuss; by USPS. Not so with UPS. They need a physical address, not a post office box number. I happen to winter in a mobile home park which has private streets not recognized by USPS. Hence his problem. He had no name to look up and only a PO box #. However, the tail lamps were just what I wanted and they arrived in good shape.


work great on my dad car trailer. great light for price.




Not the first time I have ordered from etrailer.
products, good prices and always shipped quick


Everything is great and the shipping was fast. Always good to deal with you guys. Thanks.


Lights were exact replacement for the ones I installed 30 years ago.
The old ones were getting intermittent due damage over the years.


Product exactly as advertised. Perfect form, fit and function. No surprises!


Easy to adapt these tail lights using existing drilled holes. Awesome product replacement. Fast ship. Great customer follow up!


Quality items, web site had detailed item specifications & dimensions, easy on-line ordering, and fast delivery.


Great lights. perfect for my trailer. < br>

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Info for this part was:

Employee Tricia G
Written by:
Tricia G
Employee Brian T
Updated by:
Brian T

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