The cigarette lighter plug with a cover made of durable, flame-retardant hard plastic prevents your devices from overheating, overcurrent, overvoltage, overloading, and short-circuiting. This car dual USB socket can be easily installed by connecting the red wire to the positive terminal and the black wire to the negative terminal. Short circuit and overheating protection: This prevents your devices from overheating, overcurrent, overvoltage, overloading, and short-circuiting.