Surface Mount (Flange Mount) 21 LED Truck, LED Side Marker Lights for Trailer, LED Tail Lights, Turn Signal Lights, Tail Lights, Truck and Trailer, Brake Lights, Camp Lights -car. Outer surface mount measures 7" long x 3" wide; Actual light measures 6 inches long x 2 inches wide; 4 screw holes for mounting; Wiring: White=Negative, Black=Tail Light, Red=Brake Light Positive. 21 Diodes: Each diode has a round bead-shaped reflector giving the light a clean, personalized look and better light diffusion. Operates on 12V DC: 3 wires with 2 brightness steps, can be changed to signal light, flashing light, emergency light (relay or controller not included). Suitable for most cars, SUVs, trucks, trailers, tractors, semi-trailers, tippers, buses, boats, special vehicles, etc. For heavy duty trucks like Peterbilt, Freightliner, International, Kenworth, Mack and Trucks. Weather resistant, ready for exterior mounting. Application: Trucks, trailers, tractors, semi-trailers, dump trucks, special vehicles, etc. Features: Waterproof. Oval LED lights 21 red diodes with 4 screw holes for mounting 3 wires for ground, brake/turn signal, and tail light functions.< /p> Outer mount measures 7" long x 3" wide. Actual light measures 15 .2 cm long x 5.1 cm wide. Convert your old incandescent bulbs into more modern LEDs. < p>LEDs are brighter and faster, consume less current and generate less heat than incandescent bulbs. Voltage: 12 V. < p> Each diode has a round bead-shaped reflector giving the light a clean, custom look and better light distribution. Connection Tips: White wire is ground; the common thread is high brightness; the black wire is the low light. Package contents: Set of 2 oval tail lights 21 red LEDs with 4 screws 15 cm with reflector