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When you need dependable lighting at the back of your trailer, this round 4-5/16" diameter light does it all. It serves as a stop, turn, tail, and license plate light, giving you four essential functions in one housing. The built-in license plate light keeps your tag visible and road-legal, while the standard 2057 incandescent bulb delivers consistent illumination on any 12V DC system.
Bumpy roads and vibrations can be tough on bulbs, but this light’s shock-proof socket helps protect the 2057 bulb from damage. The durable plastic housing and snap-on red lens add strength while keeping maintenance simple. If the bulb ever needs replacing, you can swap it out easily without breaking out special tools.
Installing this light is straightforward thanks to its built-in studs and clean 2-wire design. The mounting studs are spaced 2" center-to-center, so you just line them up, tighten them down, and hook up the power lead and ground wire. It’s a quick install that stays secure once mounted.
With a power draw of 2.5 amps for stop/turn and 1.0 amp for tail at 12.8V, this light fits right into standard trailer wiring setups. It’s non-submersible and surface mounts easily for solid everyday use. Backed by a 3-year warranty, it’s a simple, reliable way to keep your trailer visible and safe on the road.

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today, we're going to be reviewing Part Number ST25RB. This is the 4-3/8" Round Trailer Tail and License Plate Light for the left hand side of your trailer. You can see down here, it's got a nice, clear part of the housing that's going to allow lights come through, so it's going to send some light down to the license plate area. The red, round trailer light is going to serve four functions. It's going to provide your stop and turn signals, your tail light signal, and your license plate illuminator. It's got a black, polymer housing that's made out of a durable plastic material. It's also going to feature replaceable lens and bulb that is an incandescent bulb.
Here on the rear of the housing, you can see that it has the stud mounts on it. It's also going to include the nuts that are on there, that way, you can get it fully installed. If we take a measurement to distance between those two studs, center on center, it's going to be right on 2". The wiring design is going to have the two lead wires for power, and then it's going to ground through the mounting hardware. If we take a look at the overall diameter, it's going to give us a diameter of 4-5/16", with a depth, just going to the back of the housing, of about 3-5/8". Now, we're going to go and connect this to our external power source.
That way, you can see what it looks like with power running to it, and with our overhead lights turned off. The brown wire is going to be for the tail light function, and then the red wire is going to be for our brakes and turn signal. You can see here, it's going to send out a nice, consistent signal. This is going to be the tail light function. You can see that that 00:01:54 allows the light to come through here at the bottom. That's going to be our license plate illuminator.
Then, when we apply our breaks, you can see how it brightens up, sends out a stronger signal. It's going to be the same thing when we activate our turn signals as well. That's going to do it for today's review of Part Number ST25RB. This is the Round Trailer Tail and License Plate Light for the left hand side of your trailer from Optronics. If you need one for the right hand side, you can find that right here at etrailer.com with Part Number ST24RB. .
Customer Satisfaction Score:
96% were satisfied with this product
4% of customers were not satisfied
Ratings & Reviews

Tom
5/26/2016
Product works as well as on day one. Tom
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Walter
10/8/2022
Well after a year or so the lights work perfect! No complaints, I have been fishing several times and the lights always get submerged and light up under water when launching and receiving my boat. Starting next season I will be unplugging them before backing into the water. Like all things they will ware out. This act will just prolong that. Im going to oder some running lights soon cause dome are not working. I will replace all of them at once. Thanks for contacting me Walter