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LED Mid-Ship Turn Signal and Side Marker Light - Submersible - 10 Diodes - Amber Lens

LED Mid-Ship Turn Signal and Side Marker Light - Submersible - 10 Diodes - Amber Lens

Item # STL75AMFB
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7-7/8" x 3-5/16" Oval. Waterproof, LED trailer light serves as both a side marker and turn signal. Durable polycarbonate housing and lens. Reccess mount with built-in flange. Accepts weathertight plug. E rated. Lowest Prices for the best trailer lights from Optronics. LED Mid-Ship Turn Signal and Side Marker Light - Submersible - 10 Diodes - Amber Lens part number STL75AMFB can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (11)
  • Q & A (0)
  • Videos (1)
  • Photos
  • Why etrailer?

Optronics Trailer Lights - STL75AMFB

  • Clearance Lights
  • Oval
  • LED Light
  • Amber
  • 7-7/8L x 3-5/16W Inch
  • Recessed Mount
  • Side Marker
  • Turn
  • Submersible Lights
  • Optronics

7-7/8" x 3-5/16" Oval. Waterproof, LED trailer light serves as both a side marker and turn signal. Durable polycarbonate housing and lens. Reccess mount with built-in flange. Accepts weathertight plug. E rated.


  • Oval trailer light serves as a side marker light and mid-ship turn signal when properly mounted
    • E rated for vehicles 30' or longer
  • Sonically sealed, waterproof housing and lens unit is submersible
  • LEDs make great replacements for incandescent lights
    • Last 50 times longer
    • More efficient - provide brighter light with less power output
    • No bulbs to replace - no brittle filaments
  • Durable polycarbonate housing and lens
  • Amber lens over white LEDs
  • Compatible with 12V DC systems
  • Recessed mount with built-in flange
  • Accepts weathertight plug (sold separately)
  • P2 rated produces a 90-degree beam pattern


  • Dimensions: 7-7/8" long x 3-5/16" tall x 2-1/2" thick
  • Distance between mounting holes (center on center): 6-15/16"
  • Diodes: 10
  • Power draw at 12V:
    • Turn: 0.201 amps
    • Side marker: 0.054 amps
  • Lifetime warranty on LEDs

Optronics STL175AMFB LED Mid-Ship Turn Signal Marker Light Dimensions

Sonically Sealed, Waterproof Trailer Light

The waterproof construction of this light makes it ideal for use on trailers that may be submerged, like a boat trailer. The housing and lens are sonically sealed together to create a single unit, which means that water will not get into the light and damage the diodes or circuit board.

P2-Rated Lights

Diagram of light spread for P2 rated light

A P2-rated light produces a 45-degree angle of light to either side of its centerline for a total of 90 degrees of coverage. This beam pattern can be seen straight on, but it cannot be seen clearly from the side. So this type of light can be used as either a side marker light or a clearance light, but it cannot function as both. If you need both functions, then you must install 2 separate lights on your trailer - one as a front or rear clearance light and one as a side marker light.

Weathertight Wiring Connection

Optronics Weathertight Connection

This light has a weathertight connection as pictured above (weathertight plug sold separately). This type of connection is designed to help block out moisture.

Recessed-Mount Light

Recessed-mount trailer lights install with a grommet, which is often sold separately. These lights extend past the trailer surface and require a hole for installation. If replacing a light, you can utilize the pre-existing hole. If installing a new light, you will need to cut a hole or use a mounting bracket (sold separately) to complete the installation.

STL75AMFB Optronics LED Mid-Ship Turn Signal and Side Marker Light - Submersible - Weathertight Connection - Oval - Amber Lens - Recess Flange Mount - P2 Rated

California residents: click here

Video of LED Mid-Ship Turn Signal and Side Marker Light - Submersible - 10 Diodes - Amber Lens

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Optronics Trailer Lights - Clearance Lights - STL75AMFB Review

Today we're going to be taking a look at the Optronics Amber LED Mid-Ship Turn Signal and Intermediate Marker Light. This light is going to contain a total of ten amber LEDs. LEDs are going to be great replacements for incandescent lights. They last longer, they burn brighter, and they're much more efficient. You don't have to worry about replacing bulbs and you don't have to worry about brittle filaments. Optronics is actually going to put a lifetime warranty on the LEDs.

You can see here that it has this extra piece going around that's built into the housing, but that's going to be the flange, so this is designed to be a flange mount installation. You've got the two mounting holes, one located on either side. Those are going to be separated apart from one another center on center by about seven and one eighth of an inch. Hardware is not included, so you will need to provide that separately. Here on the back side you can see the plug type that it would accept. This is going to accept the Optronics weather-tight plug.

Those are going to be sold separately. We offer a couple different variations of those plugs here at This unit does meet Department of Transportation FMVSS108 requirements for e-rated mid-ship turn signal and P2 intermediate side marker light. The unit is going to be sonic-ally sealed, so it's got a nice waterproof lens and housing. Optronics, again, is going to put that lifetime warranty on the LEDs. A few measurements to go over with you real quick, starting with the overall length.

Measuring from edge to edge that's going to give a measurement of about seven and seven eighths of an inch. The overall width, that's going to give a measurement of three and five sixteenths of an inch. The depth overall, including the plug there at the back, that's going to measure two and a half inches. That was from the back of the plug to the very top of the light. If we just measure from the flange piece to the top of the light that's going to give a measurement of ...

looks to be about one and three eights, one and five sixteenths of an inch. Right in that area. If you do not include the flange in the measurements we're looking at an overall length from this point here to this point here of about six and a half inches. With an overall width from this point here to this point here of about two and three eighths of an inch. What I want to do now is simply just go ahead and hook it up to our external power source. That way you can see what it looks like with power running to it. The plug simply just goes into this area right here. You push it in. It's got this tab on it that snaps over the nib that comes off of the housing of the light. That's really going to secure the plug into place, and that had a nice cushion sealer on it, so once it engages that's going to create that nice weather tight seal. We'll also be able to turn off our overhead lights. That way you can see it in a low light setting. This is going to be the side marker function. It sends out a nice consistent signal. Again, ten LEDs and then when we apply our turn signals you can see how that illuminates for a stronger signal output. The multi-dial design really does allow a lot of light to come through. It's going to optimize our light output. That's going to do it for today's look at the Optronics Amber LED Mid-Ship Turn Signal and Intermediate Marker Light.

Customer Reviews

LED Mid-Ship Turn Signal and Side Marker Light - Submersible - 10 Diodes - Amber Lens - STL75AMFB

Average Customer Rating:  5.0 out of 5 stars   (11 Customer Reviews)

7-7/8" x 3-5/16" Oval. Waterproof, LED trailer light serves as both a side marker and turn signal. Durable polycarbonate housing and lens. Reccess mount with built-in flange. Accepts weathertight plug. E rated.


Very very good customer service. Lights were exact fit. We will definitely order again.


Thanks for fast shipping and quick resp onse.


Number one


These were installed on a box truck that had no side markers. They're extremely bright and make the turn signal quite obvious to drivers in other lanes that cannot see the rear lights. These were a major improvement in safety for our truck.


I’m giving e-trailer parts a Five Star solely on the logistics process. I initially put a P.O. Box down for the delivery and within 15-30 minutes of placing the order I received a phone call for a physical location so they could begin processing and shipping my order. I probably would have still given them a 5-star if I received the right item, but that was an issue on my behalf. I went off of the image and thought it was the light I needed due to the holes on each end but it was bigger than what I needed. Overall I highly recommend e-trailer to anyone whose looking or needing replacement parts for their Trlr.


Excellent product. Good quality. Works very well.

My LED lights are bright and reliable.
James - 08/13/2019


Worked and fit as advertised. Installed on a class A motorhome.


Great service





Ask the Experts about this Optronics Trailer Lights

  • Is the Amber LED Mid-Ship Turn Signal Part # STL75AMFB Sold in Pairs
    The Amber LED Mid-Ship Turn Signal part # STL75AMFB is for a single light. If you need a pair of them then you would want to enter "2" into the quantity box on the product page.
    view full answer...
  • 6-1/2 x 2-1/4-Inch Amber LED Light for 2008 Mastertow Tow Dolly
    I checked photos of the Mastertow tow dollies and I saw some with oval amber lights in what looks like the 6-1/2 x 2-1/4-inch size you mention. We do have an amber LED clearance light that matches your dimensions, part # STL75AMFB, which is intended to serve as a mid-ship turn signal. This light has pigtail leads rather than a 3-prong receptacle. On the linked page you can see all amber LED-type lights we offer. You can click on the filters to narrow down the items shown based on light...
    view full answer...
  • Wiring Harness Recommendation for Optronics Light # STL75AMFB
    The pigtail harness needed with the Optronics light part # STL75AMFB that you referenced is part # A45PMB.
    view full answer...
  • Add Separate Trailer Turn Signal Lights
    Please take a look at the Curt 2 to 3 Wire Tail Light Converter, # C56196. Pair this converter with an isolating diode kit, # 38955, to get the signal you are looking for. This is actually designed for use of flat towing a vehicle behind a motorhome, but the same results are achieved for what you are wanting, separate signal lights. It is rather straight forward, see the attached diagram. Remember that although wiring color code is identified, attach wires function to function even if...
    view full answer...
    Image 1 for
  • Installation of Midship Marker and Turn Signal Light on 1996 Holiday Rambler Endeavor
    Good news! I can help you wire up a mid-ship turn signal your 96 Holiday Rambler Endeavor, but the Optronics light # MCL32AB you asked about will not blink while you have the running lights on. What you will need is the Amber LED Mid-Ship light with flange # STL75AMFB. I recommend using butt connectors # DW05714 and 16 gauge wire # 16-1-1 to make the connection to the diode from the original circuits. I have linked all the above mentioned products to this page for your purchasing convenience.
    view full answer...
  • Remote Charge Controller for Lithium Lifepo4 Battery
    The Go Power MPPT Solar Charge Controller - LCD Digital Display - 60 Amp item # GP54FR has an optional remote. It is the Remote for Go Power MPPT Solar Charge Controller item # GP34FR. This system works with Lithium batteries like the Power Sonic RV Lithium Battery - LiFePO4 - Bluetooth - Group 4D - 12V - 200 Amp Hour item # PS64FR or the 100 Amp Hour item # PS94FR. It also works with our largest LiFePO4 Power Sonic RV Lithium Battery the 300 Amp Hour item # PS74FR. It also has a Bluetooth...
    view full answer...

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Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Cole B
Installed by:
Cole B
Employee Brian T
Updated by:
Brian T

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