DC5.5mm x 2.1mm 12V automatic power adapter coiled cable is for car,truck,bus,truck,boats,etc.And this 12v adapter is universally suitable for most household appliances,such as portable car air-pump,DVD-players,,external-hard drive,LED light, The extension length of this power adapter coiled cable is about 3.3 feet, and the unstretched length is about 1.3 feet.It can be used as an extension cord DC12V car cigarette-lighter ,built-in replaceable fast-acting 3A fuse-to protect your car circuits and equipment.Cigarette lighter-plug with LED light: LED indicates whether you are working. This - automatic power adapter coiled cable, convenient for you to power other devices through the car when you go out.The big end is inserted into the car , and the small end is 5.5x2.1mm/3.5x1.35mm/4.0x1.7mm DC-plug The input - is equal to the output -, which is suitable for products- with a 12V 24V - . The input - is 12V, and the output - is also 12V