Iztor 24v Car Motorcycle boat RV Motorbike Cigarette Lighter Power Plug Socket without wire Including 24v Cigarette Lighter and 2 15cm wires Outer diameter: about 28 mm Installation: Connect the red wire with round terminal to the round pin of socket and the black wire with flat terminal to the flat pin. Then connect the red wire to battery's positive (+) terminal and black to negative (-) terminal. Applications:GPS charging, cell phone charger, car MP3 power supply, car vacuum cleaner, car tire inflation power, etc.