1T-400R is a Four Inch Round Incandecent Tail lamp Kit. This Kit Comes Complete with a 4 Inch Mounting Grommet and a Three Wire Pig Tail. This is your basic Incandescent Trailer Light Kit, Great for replacing damaged Tail Lamps used with Trailers and Many Other Vehicles. This Light is a SAE/DOT certified Multi-Function Stop Turn Tail Lamp. An excellent Long Lasting Tail Lamp with special vibration dampening secureing the Incandcent Bulb Light Source. The light mounts with 4 Inch Grommet which is Included in the Kit.