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When your trailer gets exposed to rain or water, this 4-1/4" round LED light stays sealed tight. The polycarbonate lens and housing are completely waterproof, making it a solid choice for use around water or harsh conditions. The sealed design protects the single red LED from moisture and corrosion while keeping performance consistent. You get a light that keeps shining bright trip after trip without worrying about leaks or failures.
Wiring can be one of the trickiest parts of trailer lighting, but this light makes it simple and secure. The built-in weathertight plug helps block moisture and dirt from getting into the connection points. It’s designed to use adapter AL45PWTB (sold separately) to work with standard 3-prong setups, giving you a clean, protected link between your trailer and vehicle.

Visibility matters when you’re out on the road. This single-LED red light handles brake, tail, and turn signals with sharp clarity—glowing steadily for tail lights, brightening for brakes, and flashing for turns. At 12.8V it draws just 0.25 amps for stop/turn and 0.007 amps for tail function, keeping power demand low while still delivering bright output. It’s more efficient and durable than traditional bulbs, backed by a lifetime warranty on the LED.
Getting lights to sit flush can make all the difference in how your setup looks and performs. This one mounts neatly in a cutout using its built-in black flange for a streamlined fit that won’t snag or stick out awkwardly. With overall dimensions of 5-1/2" diameter x 1-11/16" thick and a 4-1/4" face, it’s compact yet substantial enough to give your trailer lighting a clean, professional finish that’s DOT compliant and meets FMVSS 108 and CMVSS 108 standards.

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we're going to be taking a look at part number StL003RFMB. This is the Optronics ONE LED trailer light. The round trailer light is going to serve three functions, providing your stop light, taillight and turn single light. It is going to feature a sonically sealed waterproof housing and lens unit. It is completely submersible. The ONE Series is going to provide bright light using a single diode unlike other LEDS that use a multi diode design. The ONE Series is one LED.
It's going to feature durable surface-mount technology when it comes to the construction of the LED circuit board. That's going to better withstand shock and vibration, and it's going to allow for improved heat distribution. Now, LEDs are going to make great replacements for incandescent lights. They're going to last longer. They're much more efficient. They burn brighter.
You don't have to worry about replacing the bulbs, and you don't have to worry about brittle filaments. It's going to feature the polycarbonate red lens and the polycarbonate black housing, very strong and durable. This is a recessed mount installation. It's got the built in mounting plans. It's going to contain three mounting holes. You're hardware is not included.
We take a measurement of the diameter of the recessed area from this point right here to this point right here. That's going to give us a measurement of about 4 1/2 inches. The depth of the recessed portion, measuring from the back of the flange to the back of the plug, is looking at about 1 13/16 of an inch. Now, the plug back here is going to feature a weather tight connection point on the back of the light. It does require an adapter, part number AL45PWTB that is sold separately, and it is required to work with the industry standard three-pronged plug. The light is Department of Transportation compliant. If we take a measurement of the diameter of the light face, basically just measuring that lens area, that's going to measure 4 1/4 of an inch.
Overall diameter, including the flange, you're looking at about 5 1/2 inches. Overall depth from the front of flange to the back of the plug, we're looking at about 2 inches deep. Now our mount holes are going to be separated on center apart from one another by 4 1/4 of an inch. That's going to be the same distance between each mounting hole, and those holes are going to give us a diameter of about 1/4 of an inch. Again, this light is going to contain one diode or one LED. The power draw at 12.8 volts for the stop and turn light is 0.25 amps and for the tail light is 0.007 amps. Optronics is going to put a lifetime warranty on the LED. We're going to go and hook it up to our external power-supply that way you can see what it looks like with power running to it. We'll take our plug and place it into the back portion here until it clicks into place. You can see here that it has the one LED. It sends out a nice consistent signal. This is going to be the tail light function. Then when we apply our breaks, you can see how that illuminates for a stronger signal output, and it's going to do the same thing when we activate our turn signal. That's going to do it for today's review of part number STL003RFMB.
Ratings & Reviews
Bought to replace existing weathered lights in a heavy trailer. Looked the same as depicted but my frame around lens was metal ,not plastic like the ones I received. I will use them, exact fit, but I doubt they will take the abuse the original did over the years
Nice, bright, submersible lights!
Excellent replacement light for my trailer. Fit well. Etrailer has outstanding prices and ships fast.
Just opened box seams to be everything ordered,will install lights over weekend an see if all work ,will let you know.1994 gooseneck be comning new.
led trailer light for my tralor worked grate still going. low price I actually bought two at diferent times and they work grate.
been working great for 1 year.
Led lights are the way to go.
No more bulb problems
Had a scratch on one of the lenses upon receipt. I notified e-trailer, they handled it right away sending q replacement. It’s nice to see that customer service does still exist. Thank you
Can't wait hooking up that trailer for a nighttime cruise knowing i got my One LED Trailer lights protecting my backside!
Used these lights to upgrade to LED on my triple Axel equipment trailer. Lights are nice and bright. Would have given 5 stars except that since I have ordered these lights I have been bombarded with trailer light advertisements that just won't quit.
I replaced the burned out light on the horse trailer. Very easy to install....Pull the old light out of the rubber casing, unplug, and reverse directions for installation....No Tools Needed!!!
EXCELLENT SERVICE & SHIPPPING WAS FAST TY
The light fit well as a replacement without having to modify the mount. I have not had any problems with the operation but the brightness was a little underwhelming.
Great service as always
Great product to replace incandescent lamps . Bright and easy to install . Great and easy shopping on website. Quick shipping and low cost shipping too! Will buy again when needed.
It worked for my burnt out light.I had to adjust some parts of the plug in but fit was perfect and changing to led lights are much brighter.
It works great and should last a long time should have bought one for the other side
I'm very happy with my purchase. It meets my expectations. Thanks. I'll be doing some more purchasing in the near future.
I replaced my older lights with 4 of these LED units. Works great.
LED lights work great on my 73 CJ5. Have had them now for a year and no issues at all. Thanks etrailer.
The brake lights were installed, and they worked! The price was good, the service and delivery was good. No complaints all was good! :O)
Lights worked perfect for my flatbed light upgrade,great price and this company has a nice easy to use website, i only wish they came with a gasket to go between the light and the mounting surface , but with that being said not all builds need to be water tight so i still guve it five stars
Doesn’t come with wiring harness, I was able to find a wiring harness plug that worked on Amazon that was much cheaper than what was quoted from a trailer.
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Juan I.
5/10/2018
Theyre working just fine. Im very happy with the products.