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Flange Bracket for 4" Round Trailer Lights - Plastic

Flange Bracket for 4" Round Trailer Lights - Plastic

Part Number: A45BB
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This black plastic bracket allows you to flush mount your Optronics 4" round trailer light. The light snaps into the bracket for a clean look when installed. Recessed mount. Durable plastic construction. 1-800-940-8924 to order Optronics accessories and parts part number A45BB or order online at Free expert support on all Optronics products. Great prices and Fastest Shipping for Flange Bracket for 4" Round Trailer Lights - Plastic. Accessories and Parts reviews from real customers.
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Optronics Accessories and Parts - A45BB

  • Trailer Lights
  • Mounting Hardware
  • Brackets
  • Optronics
  • Black
  • 4 Inch Diameter

This black plastic bracket allows you to flush mount your Optronics 4" round trailer light. The light snaps into the bracket for a clean look when installed. Recessed mount. Durable plastic construction.


  • Bracket allows you to flange mount your Optronics 4" round trailer light
    • Designed to fit Optronics 45 Series lights (sold separately)
  • Open back provides easy access when wiring
  • Light snaps into flange for a finished look
  • Durable plastic construction
  • Flush mount installation - hardware not included


  • Outer diameter: 5-1/2"
  • Inner diameter: 4-9/16"
  • Mounting depth: 1"
  • Distance between mounting holes (center on center): 4-1/4"

Optronics Black Plastic Mounting Flange for 4 Inch Round Flush Mount Lights Diagram

Manufacturer Cross Reference
Flange will work as an exact replacement for:
Uni Bond # FL4001
Peterson # 424-09

Manufacturer Specifications

For use on 4" flush mounted tail lights, the plastic flange snaps around the light to provide new flange mounting holes. No grommet required.

A45BB Optronics Replacement Black Plastic Mounting Flange for 4" Round Sealed Lights - Recessed Mount

Alternate part number: A-45BB

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Flange Bracket for 4" Round Trailer Lights - Plastic - A45BB

Average Customer Rating:  4.7 out of 5 stars   (18 Customer Reviews)

This black plastic bracket allows you to flush mount your Optronics 4" round trailer light. The light snaps into the bracket for a clean look when installed. Recessed mount. Durable plastic construction.


It was just about a perfect fit as a replacement, the original holes were not wide enough for the rubber grommet style holder, this model fits in snug and the trailer lights are all fixed and working perfectly.


The trim rings turned the replacement of my stop / turn lights on my trailer into an easy job. They allowed for mounting of the LED replacements with no modifications needed. It was an exact fit in the holes that my old ones formerly occupied. Kudos to for having them.


This item was as described and allowed me to convert a conventional tail light to a LED tail light on my motor home. I was satisfied and will order this again should the need arise. Satisfied customer.


As always etrailer wants it right the first time. This last order was about trailer lighting (LEDs) and I want the best I can get so I urge you as the customer to do your homework as etrailer has done theirs. I also bought new wire, this has been a one stop shop for me.
Thank you etrailer ??!


I had 4” led lights from a different vendor and needed the flang to mount them. Fit perfectly. Wish they weren’t plastic but it does allow me to remove the light if need be. Overall a good buy.


Great product, prefer this much more than the rubber gasket. Made a very nice and neat installation.


The product is good quality, matches the bolt-pattern of the hanging bracket BK45BB, and fits the turn/park light STL23CCAB. The tolerances for this combination of items is very snug however, and may require some minor sanding to fit the bracket without a lot of force.


product was as advertised and promptly delivered. The fit was very tight for my Winnebago motor home but it worked fine. The exit for the wiring comes off the bottom instead of the side. That was my fault for not checking. I made it work.


Fit perfectly. Great replacement for our bus lights.


Easy installation and work great!


does not seal like a gromet would but a little calk fix that for my app. which fit into a water tight compartment.


The flanges are durable.
1 yr. later,
I still do not think about them having issues.


Very prompt delivery. Part was exactly as described.


Exactly what was needed, makes the job of hanging lights much easier


everything fit great





Extra parts just in case


See what our Experts say about this Optronics Accessories and Parts

  • Can the Optronics Sealed, Miro-Flex Trailer Clearance Trailer Light Be Used as a Brake Light
    The 3 diodes in the Miro-flex light, # MCL51RB, would not make a very good brake light. They would not be as bright as the regular brake lights already on the trailer. You would need a light designed to function in whole or in part as a brake light such as # STL23R24B. With this light you would also need a wiring harness, # A47PB. To mount it you could use mounting bracket, # BK45BB and grommet # A45GB. You could also flush mount it using the mounting flange # A45BB.
    view full answer...
  • Does Plastic Mounting Flange # A45BB Work with Other Light Brands
    Provided that the light is the correct size the brand of light will not matter when it comes to Plastic Mounting Flange # A45BB. The overall diameter of the lights that fit the flange is 4-5/16 inches.
    view full answer...
  • Weathertight Wiring Plug and Stainless Steel Bracket for 4 GloLight LED Trailer Tail Light
    There are 2 different possible connectors you can use for the wiring when it comes to the GloLight LED Trailer Tail Light # STL101RMB; the 3-Wire Pigtail # A45PMB which installs using splicing, and the Three-Wire Straight Pigtail # AL45PWTB which connects to the industry standard 3-way connector for lights. Please note that if you will be using the splicing method then you want to use heat shrink butt connectors like what comes with the kit # DW05743-10 as they will be much more effective. When...
    view full answer...
  • 24 Volt Compatible 4 inch Diameter Trailer Clearance Light Recommendation
    You'd need the part # STL23R24B for red and then # STL23A24B for amber. These are 24 volt compatible lights very similar to the one you referenced. For a mounting ring you then would want the part # A45BB.
    view full answer...
  • Will Plastic Mounting Grommet Work With Optronics 4-Inch LED Trailer Tail Light
    I called my contact at Optronics and asked about the grommets available for the # STL101RCB lights you purchased. They told me the plastic grommet, part # A45BB will work great with the lights. To complete the installation you will need the three-wire plug, either part # A45PB or # A47PB.
    view full answer...
  • Availability of an Amber Trailer Light that has Parking and Turn Signal Lights In One for a Hot Rod
    I am sorry but at this time the only trailer lights that serve two or more functions are the tail lights. There are amber tail lights that provide running light and turn signal function (see link) but none that are as small as the 2 inch round side marker light, item # MC52AB. We do have the Sealed, 4 inch Round Trailer Turn Signal and Parking Light, Flush Mount - Amber, item # ST45AB, and the Sealed, 4 inch Round LED Trailer Turn Signal and Parking Light, Flange Mount, 10 Super Diode-Amber,...
    view full answer...
  • LED Taillight Recommendation for a 1968 Heilite Trailer
    We have exactly what you need, but the # 294-0967 is for tow bar lighting for vehicles that are getting flat towed so it wouldn't be a good choice for you. For a similar light to what you have on your trailer that would be LED I would recommend the # STL23R24B. For a wiring harness you would want the # A45PB. For a mounting flange you would want the # A45BB.
    view full answer...
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  • Are there Replacement Tail Lights for a 1982 Scamp Trailer
    In order to determine which replacement lights will fit your 1982 Scamp trailer, you will need to find the manufacturer and model number of the light assembly. This could involve removal of the assembly. If you see numbers on the lens, those are not the correct numbers. If you cannot find any manufacturer/model number information, you will need to measure the diameter of your existing tail lights and any other dimension that you can. You will also need to determine how they mount to the...
    view full answer...
  • Functions of Optronics 12 Diode Miro-Flex Tail Light # STL23RB
    The Optronics 12 Diode Miro-Flex LED Trailer Stop/Turn/Tail Light you referenced, part # STL23RB is a three function lamp. The # A47PB right angle pigtail, which is sold separately, has a white ground wire, a red wire that carries the brake and directional signal and a black wire that serves as the running light circuit. If the vehicle headlights were turned on, the lamp would be lit. Applying the brakes would make the lamp brighter. The lamp has several mounting options. It can be...
    view full answer...

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Info for this part was:

Employee Michael H
Expert Research:
Michael H
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Brian T
Updated by:
Brian T
Employee Cole B
Installed by:
Cole B

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