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Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Red Lens
Optronics

Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Red Lens

Part Number: MC66RB
In Stock
$4.08
Trailer Lights
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4" x 2-1/16". Incandescent trailer light functions as a clearance and side marker light when properly mounted. Dual bulb design increases light output. Snap-on lens. Surface mount to trailer - hardware not included. PC rated. (2) 194 bulbs. Great Prices for the best trailer lights from Optronics. Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Red Lens part number MC66RB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (107)
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Optronics Trailer Lights - MC66RB

Highlights

  • Brighter Visibility at Night: Dual-bulb design boosts light output for safer towing.
  • Two Jobs in One: Works as clearance and side marker light when properly mounted.
  • Simple Wiring: 2-wire design with power and ground makes hookup straightforward.
  • Easy Upkeep: Uses two 194 bulbs that are simple to replace when needed.
  • Tough Build: Durable ABS housing and snap-on red lens hold up to regular use.
  • Road Legal: PC-rated and DOT compliant for required 180° light coverage.

Features to know about

Stronger Visibility and Coverage: Dual-Bulb Red Clearance and Side Marker Light

Good lighting is key for safety on the road. This 4" x 2-1/16" oval Optronics light uses two 194 incandescent bulbs to push out a bright, even glow that’s easy to see from across the lane. The dual-bulb design increases output compared to single-bulb setups, boosting visibility when used as both a clearance and side marker light. With its PC rating, it throws light 90 degrees to each side of center for a full 180-degree spread—drivers can see it from the front or from the side, helping mark your trailer’s corners clearly.

Simple Surface Mounting: Easy Installation with 2-Wire Hookup

Wiring and mounting shouldn’t slow you down. This light surface mounts directly to your trailer using standard hardware (not included) with mounting holes spaced 3" apart center-to-center. The two-wire design keeps things simple: one power lead and one ground wire. It works with a standard 12V DC system, so you can tap into your running light circuit and be ready to go in minutes.

Durable Construction: Tough ABS Housing with Snap-On Lens

When you’re dealing with vibration, weather, and road grime, durability matters. This light uses a sturdy ABS housing and a red snap-on lens that holds tight once it’s in place. The design lets you replace the bulbs easily when needed, without replacing the whole fixture. It’s built for long service life as a non-submersible unit, giving dependable performance for everyday trailer use.

Reliable and Compliant: DOT Approved for Road Use

You shouldn’t have to wonder if your lights meet standards. This PC-rated clearance and side marker light is fully DOT compliant, giving you peace of mind that it meets safety requirements for on-road trailers. With a power draw of just 0.2 amps at 12.8V, it’s efficient while still being bright enough to do the job right.

Specs

Dimensions

  • Dimensions: 4" long x 2-1/16" tall x 1-1/16" thick
  • Distance between mounting holes (center on center): 3"

Dimensional diagram of Optronics MC66 dual-bulb red oval trailer clearance and side marker light showing 4 inch by 2-1/16 inch size and 3 inch mounting hole spacing

Electrical

  • Bulb type: 194
  • Number of bulbs: 2
  • Power draw at 12.8V: 0.2 amps

Diagram showing 180-degree beam pattern of a PC-rated trailer clearance and side marker light demonstrating 90 degrees of light to either side of centerline

  • A PC-rated light produces a 90-degree angle of light to either side of its centerline for a total of 180 degrees of coverage. This beam pattern can be clearly seen when you are standing directly in front of the light, as well as when you are standing on either side of the light. When properly installed, this type of light can function as both a front clearance light and a side marker light or as a rear clearance light and side marker light.

Warranty

  • Warranty: 3-Year

MC66RB Optronics Dual Bulb Trailer Clearance and Side Marker Light - Incandescent - Oval - Red Lens - PC Rated

Alternate part number: MC-66RB





Customer Satisfaction Score:

Ratings & Reviews

4.8

107 reviews
Review sort icon
4" x 2-1/16". Incandescent trailer light functions as a clearance and side marker light when properly mounted. Dual bulb design increases light output. Snap-on lens. Surface mount to trailer - hardware not included. PC rated. (2) 194 bulbs.

by:

You cab buy these in regular automotive stores for 5 up to 15 dollars. Great price. These simple things shouldn't cost anything more!



by:

Works as expected with no issues!



by:

Classy piece-gets lots of compliments!



by:

Put these on my camper. They all still work a year later. Can't beat the price.



by:

Product is exactly what I needed for my 2002 trailer.



by:

These lights are nice, just wish they came with a weather seal.



by:

so nice to work with a very professional company...
once installed, will send pictures..
thanks,

Park

Park L. profile picture

Park L.

6/21/2016

all worked great... nice company



by:

Two wire, two 194 bulbs. Cover locks on great. will buy again



by:

Excellent service. Received items earlier than expected. Good packaging. Nothing damaged. Overall great customer service and a pleasure doing business with this vendor. Will definately use this company again.



by:

Price great! Lights arrived promptly! Installation easy and they work great!



by:

2nd time ordering. Economical shipping was $5 and still made it 4 state in 3 days!! Parts are exactly what i wanted and cheapest i could find!!!



by:

Great company to work with, products as listed, great customer support through the process including having to change my order!



by:

Very happy and great buying experience great product and quick shipping !



by:

Though this is a more modern version of the marker lights that were on my 1995 Sundowner Sunlite, the holes match up for easy installation!



by:

Like the ground wire so that it is not relying on the mounting screws for the ground.



by:

Good quality replacement products

Doug S. profile picture

Doug S.

9/21/2016

Still working as it should



by:

The lights were better than expected. I couldn't believe how fast the shipping was. I can't wait to do my next order. Job well done. Thanks.



by:

Grateful I found this website, your web page is great for finding the products I needed, the price was great and free shipping on top of that. The product came quickly and although I haven't installed it yet I plan on doing that this weekend. I am very pleased with your company.



by:

I ordered replacement lights for our camper because some were not working. They were exactly what I needed. I plan to order some more and change all the other ones out.



by:

Instant response following the order confirming they received it, followed up with shipping info and tracking when shipped and received it ahead of scheduled delivery! Will only use etrailer for my trailer needs.

Thanks



by:

Great replacement for my old weathered lights. cheaper to buy new lights then just the lenses.. Yes these lights come with two bulbs installed.



by:

After the light broke on my trailer I could not find a replacement at the original manufacture, my search at etrailer paid off with an exact replacement and at a great price. Shipping was fast and on time.



by:

After working on the old lights on my camper numerous times just prior to leaving on a trip and while traveling, I decided it was time to replace all of the lights. I purchased two new tail/brake lights, and four new side markers. The total price including shipping was just over $28 (I should have done this a long time ago). The lights arrived within 3 days of being ordered, and I was able to install them fairly quickly. I am so happy that I now have all six lights working perfectly, and shouldn't have to worry about them for a long time



by:

Great replacement, looks like the vintage lights on the trailer.

Dan profile picture

Dan

8/5/2016

No problem, I think you have great replacements, only thing is.I buy used camp trailers, repair them, and resell them, so your likely to have more orders down the road, thanks.



by:

Exactly what I needed. Fast shipping.


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See what our Experts say about this Optronics Trailer Lights

  • Recommended Replacement Light/Lens for an Older Reflect-O-Lite 400
    the Reflect-O-Lite 400 light has been discontinued for quite a while so there isn't going to be an exact replacement. Instead, the closest replacement lens we have is the Replacement Amber Lens for Optronics MC66 Series Clearance or Side Marker Trailer Light # A66AB or the Replacement Red Lens for Optronics MC66RB Clearance or SIde Marker Light # A66RB. Both of these lenses measure 4" long x 2" tall x 7/8" deep, and is made of acrylic. There's no guarantee it'll be compatible with your...
    view full answer...
  • Wattage Per Bulb in Optronics Two-Bulb Trailer Clearance and Side Marker Light, # MC66RB
    The bulbs used in Optronics Two-Bulb Trailer Clearance and Side Marker Light, # MC66RB, are 194 bulbs. The 194 bulb has a wattage of approximately 3.78 watts per bulb. If you need replacement 194 bulbs you can use # A194B.
    view full answer...
  • Replacing Incandescent Trailer Lights with LED Equivalents
    There is no specific preparation procedure required to change over your trailer's lighting from standard incandescent fixtures to the brighter, cooler-operating and more efficient LED types available now. LED lighting is a great way to both improve trailer visibility and reduce power demand on your tow vehicle's wiring system. While you are going through this conversion it is a good idea to take a thorough look at your trailer's connector and wiring, from the 4-pole (or 7-way) at the trailer...
    view full answer...
  • Clearance Trailer Lights With Replaceable Lens Recommendation
    We do have clearance lights that may work for you. The clearance lights we offer come in amber or red and we have either 1 or 2 bulb units. You mentioned you like the 2-bulb feature on some clearance lights. I recommend part # MC66RB. This light comes with 2 incandescent bulbs and has a red lens. The amber version of this light is part # MC66AB. Both of these lights use the replacement bulbs, part # A194B. These are push-in bulbs. The replacement lens for the red light assembly is part...
    view full answer...
    Image 1 for
  • Does Optronics # MC66RB Incandescent Trailer Clearance/ Side Market Lamp Include Bulbs
    The Optronics # MC66RB Trailer Clearance/Side Marker Light does indeed include bulbs. Optronics also offers a similar LED lamp, part # MCL31RB. LED lamps draw a fraction of the power of incandescent bulbs, and will last considerably longer.
    view full answer...
  • Can Optronics Trailer Light # MC66RB Be Used as a Clearance Light on a 1976 Starcraft Trailer
    The Optronics trailer light, # MC66RB, can be used as a clearance light. You would need to tap into the running light circuit on the trailer wiring. You can do this anywhere along the tail light wire so if you wanted to mount it near the tail light you could do so. The white wire will need to be grounded to the trailer frame. I have included a link to a video review of this light for you.
    view full answer...

Do you have a question about this Trailer Light?


Info for this part was:

Employee Patrick B
Video Edited:
Patrick B
Employee Michael H
Expert Research:
Michael H
Employee Laura H
Updated by:
Laura H
Employee Brian T
Updated by:
Brian T

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