This Tecniq S91 LED fender light is a fully submersible and highly durable amber-red light for boat trailers and utility trailers. The trailer light surface mounts to your trailer with two screws, (not included) with 3 inch hole spacing on either side of the red and amber light. This light is the same size as Tecniqs line of S18 side marker lights, but provides fender light function for your trailer. The dual-sided fender light can be mounted on either the passenger side or driver side of your trailer, you will just orient the red light to the rear of the trailer and the orange light to the front of the trailer.