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Optronics LED Trailer Clearance or Side Marker Light - Submersible - 6 Diodes - Red Lens - 12V
Optronics

Optronics LED Trailer Clearance or Side Marker Light - Submersible - 6 Diodes - Red Lens - 12V

Part Number: MCL66RB
In Stock
$18.38
Trailer Lights
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4" x 1" Rectangle. Waterproof, LED trailer light serves as either a side marker light or a clearance when properly mounted. Durable polycarbonate lens and housing. Surface mount on trailer - hardware not included. 2-Wire design. P2 rated. Great Prices for the best trailer lights from Optronics. Optronics LED Trailer Clearance or Side Marker Light - Submersible - 6 Diodes - Red Lens - 12V part number MCL66RB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Optronics Trailer Lights - MCL66RB

Highlights

  • Reliable In Any Weather: Sonically sealed, submersible housing keeps water out and LEDs protected.
  • Fewer Replacements Needed: LEDs last 50 times longer than bulbs and draw only 0.057 amps at 12.8V.
  • One Light, Two Functions: Works as a clearance or side marker light when properly mounted.
  • Easy Fit Anywhere: Compact 4" x 1" size with 3" center-to-center holes for surface mounting.
  • Built To Last: Durable polycarbonate lens and housing resist damage from road debris.
  • Road Legal: DOT compliant and P2 rated for safe, visible trailer lighting.

Features to know about

Brighter Light, Less Power Draw: Six-Diode LED Design

Swapping out old bulbs for LEDs is a big upgrade, and this 4" x 1" rectangular light makes it easy. It uses six red LEDs under a polycarbonate lens to put out a bright, even glow while drawing only 0.057 amps at 12.8V. That means it’s energy-efficient, long-lasting, and doesn’t need bulb changes or worry about filaments breaking. It’s built to run cool and steady so you can count on consistent light every time you hook up power.

No More Water Leaks or Fogged Lenses: Sonically Sealed and Submersible

Moisture ruins lights fast, but this one’s ready for the water. The housing and lens are sonically sealed into a single waterproof unit that won’t let water inside even when fully submerged. It’s ideal for wet roads or launching at the boat ramp—no corrosion, no moisture damage, just clear reliable light each time you use it.

Easy Mounting in Tight Spots: Simple Surface Installation

This light mounts flat and secure wherever you need it. The surface-mount design has a 3" center-to-center hole spacing, so installation is straightforward with the right screws for your surface material. The 2-wire hookup—power lead and ground wire—makes wiring fast and clean without extra adapters or plugs to chase down.

Clear Designation and Safety Compliance: P2 Rating and DOT Approved

Built with a P2 rating, this light projects a 45-degree beam on either side of centerline for a total of 90 degrees of coverage—perfect for use as either a clearance light or a side marker when mounted properly. It meets DOT standards too, so it provides the right output and visibility you need for safe operation day or night.

Specs

Dimensions

  • Overall dimensions: 4" long x 1" wide x 1-3/16" thick
  • Distance between mounting holes (center on center): 3"

Technical diagram of Optronics MCL66RB LED trailer clearance and side marker light showing 4-inch by 1-inch rectangular dimensions and 3-inch mounting hole spacing, for installation reference.

  • Dimensions: 4" long x 1" wide x 1-3/16" thick
  • Distance between mounting holes (center on center): 3"

Electrical

  • Power draw at 12.8V: 0.057 amps
  • Voltage: 12V DC electrical systems

Lighting

  • Diodes: 6
  • Lens color: Red
  • LED color: White
  • Function: Clearance light or side marker light (when properly mounted)
  • Rating: P2 rated
  • Compliance: DOT compliant

Construction

  • Housing and lens material: Polycarbonate
  • Mount type: Surface mount (hardware not included)
  • Design: 2-wire (power lead and ground wire)
  • Waterproof rating: Sonically sealed, submersible housing and lens unit

Warranty

  • Lifetime warranty on LEDs:

Manufacturer Cross Reference

  • Uni Bond #: LED0750R
  • Truck Lite #: 35200R
  • Grote #: 47242
  • Peterson #: M160R
  • Maxxima #: M20340R

MCL66RB Optronics 12V LED Trailer Clearance or Side Marker Light - Submersible - 6 Diodes - Red Lens

Alternate part number: MCL-66RB





Customer Satisfaction Score:

Ratings & Reviews

4.8

3192 reviews
5 Stars
(2771)
4 Stars
(277)
3 Stars
(59)
2 Stars
(24)
1 Star
(61)
Review sort icon
4" x 1" Rectangle. Waterproof, LED trailer light serves as either a side marker light or a clearance when properly mounted. Durable polycarbonate lens and housing. Surface mount on trailer - hardware not included. 2-Wire design. P2 rated.

by:

As advertised. Lights were delivered promptly and free of any damage.
Great transaction!



by:

Perfect fit, no problem to install, great price!



by:

Excellent lights and I looked all over the net to find these particular lights and Etrailer.com had exactly what I needed and great price and fast shipping!! Will buy from this website again....



by:

Exact Replacement



by:

Teresa was very helpful in changing my order quickly and product was received timely,, Thanks Ron



by:

Great seller. Great lights. Easy install. seller followed the deal to my complete satisfaction. I will use again.

C. C. profile picture

C. C.

11/26/2015

Just fine. Great intensity and reliability.



by:

Great visibility better than the OEM that came on my travel trailer. Love-em.



by:

Fast and efficient, we have our boat trailer back in service in just few days. Thank you, and will definitely refer your site and will order again.



by:

Just as listed.



by:

Works perfectly



by:

Tip notch product and customer service. Probably the best I've experienced. I got 11 of these lights and they are obviously well made. Will definitely shop around.



by:

It would be difficult , if not impossible, to have a more helpful person facilitating the placing of an order than Paula at etrailer. I swapped out all incandescent light fixtures on my trailer with led, and the buyiing/ selection process was made a pleasure with her help.



by:

These are nice, they are completely sealed from moisture and are more than bright enough. Extra work to change the entire fixture instead of a light bulb but more than worth it.



by:

Great product and service was excellent



by:

Replace original equipment same light excellent easy installation



by:

Super Bright, cant wait to use under water !!



by:

Put these LED lights on the side of my trailer,looks great and vibrant,and there totally sealed,no maintenance .

Jim L. profile picture

Jim L.

5/26/2016

Product great, e trailer had what I needed



by:

Nice bright marker light and easy to connect to existing wire harness.

David D. profile picture

David D.

4/3/2018

The 2 amber and 2 red lights I purchased are still working just fine. Great lights and I would buy them again.



by:

Replaced exactly what I needed



by:

I bought 2 of these lights.They work great and are exactly what I needed. Customer service was great and was quick to clear up receiving the wrong light for one of them. I will use them for future purchases if needed.

Craig profile picture

Craig

11/5/2025

Still working great. No problems.



by:

Fit perfectly where the old lights were. Perfect replacement.

Brooke M. profile picture
Etrailer Expert

Brooke M.

4/14/2025

Too "light-git" to quit! [gotta say it with a sort of Australian accent for it to work]



by:

Super bright.



by:

Super bright.



by:

You guys are awesome



by:

Really appreciate your approach to real customer Service! You guys are magnificent! Thank you so very much!


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Info for this part was:

Employee Tyler C
Written by:
Tyler C
Employee Patrick B
Video Edited:
Patrick B
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Laura H
Updated by:
Laura H
Employee Brian T
Updated by:
Brian T
Employee Noah M
Updated by:
Noah M

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