This 4 Inch Round Sealed Trailer Light is one of the most common replacements for recessed lighting on utility trailers, but can also be used on marine trailers as the lights are completely sealed. This light can be submerged. It is a three function light so it acts as the stop,turn,and tail/running lights for your trailer. It mounts to your trailer using the included rubber grommet which holds the light in place once installed. The included universal three prong wiring harness plugs into the back of the light and splices into your existing harness.