This is a replacement 6" Oval Red LED trailer light. Typically this style of light mounts in an oval housing. The mounting application can be metal, or mounted into a rubber gasket (most popular. This is a Tecniq brand light, part number T66 in Red. This listing is for just the LED Light. You would use your existing 3 Prong Pigtail to plug into the back of the light, and secure it into the housing to operate the Stop/Turn/and Tail light functions. The 6" refers to all industry standard 6" oval applications. You can mount this style of light horizontally, vertically, or at angle angle of illumination. Tecniq offers a guarantee for protection on the circuit board, and rates this light IP68 for dust and waterproofing. A common question we get refers to the use of this light in Boat Trailer Pipe Lights. While this is not the exact light that comes in a Pipe Light Kit, this light can be used effectively as a replacement.