Partsam Pair Waterproof Amber 2.5" Round Marker Light Truck Trailer Boat Light 4LED Front Rear Partsam (2 x Amber) 2.5" 4LED Round Led Truck Light, Led Marker Light, Side Marker Light, cab roof marker light. Side marker and clearance light, serves as clearance, side marker or identification light, turn singal light. Compatibility: 12V trucks, trailer, boat trailer, horse trailer, travel trailer, camper, RV, motorhome etc. You can use them on any applications: left right front rear Top Roof Truck Bed Size without grommet: Outer Diameter: 81mm(3.1''), Inner Diameter: 62mm(2.4''); 2 Wires Connection: Black is the negative and red is the positive.