BiXPower Car Cigarette Female Socket to 5.5 x 2.5mm & 5.5 x 2.1mm Female Jack Adapter The package comes with one car cigarette adapter. One end is a cigarette lighter socket, and the other end is a 5.5 x 2.5mm female jack. It also comes with a connector tip (one end is 5.5x2.5mm male. The other end is a 5.5x2.1mm female jack). This adapter one end is a female socket connector like a car cigarette lighter socket in most vehicles. Another end is a 5.5mm x 2.5mm female barrel connector adapter. Female jack size on adapter is 5.5x2.5mm. It can be changed to 5.5 x 2.1mm female jack with the extra connector tip that comes with the package. The cable between the two ends is ~4 inches long and made with 18AWG wires. It can handle a maximum of up to 10 Amps current. Cautions: This adapter cable is just a connector adapter, and it does not have any electric circuits inside to control electric voltage/current/polarity. It only provides physical size and shape conversion. Please make sure the power source's voltage/current/polarity are all correct for your applications when using this adapter. If you plug the enclosed connector adapter to the cigarette adapter's female jack, then you convert the cigarette adapter's 5.5 x 2.5mm female connector into a 5.5 x 2.1mm female connector.