his 5.75-inch x 2-inch light with a replaceable high impact white plastic base and a polycarbonate lens comes with a replaceable bulb. It has a 2-screw mounting (screws included) and a 3-prong Grote(R) type connector. The torsion mount bulb cradle provides a longer bulb life and it features a shock absorbing lens cushion. Uses No.1157 replacement bulb. Help other drivers on the road gauge the size and location of your vehicle and prevent accidents resulting in poor visibility or less awareness. Powered by a reliable 12-volt system this light emits light to effectively mark your semi-truck or trailer and provide visibility on the road. Use several to outline your trailer or camper and make sure your vehicle is easily seen. Incorporate several of these sealed marker lights into your trucking setup, These lights serve as powerful aides to allow others to accurately gauge the size and location of your vehicle thus preventing accidents that can occur due to poor visibility or lack of awareness. Durable polycarbonate sealed housing and universal 3-prong Grote type connector are built to withstand the rigors of long-haul journeys. Equip your truck with these sealed marker lights to illuminate your trailer frame.