... plug into the cigarette socket DC 12V in car, then screwing the air nozzle on valve, starting ... car engine working. This type of air pump (compressor ) is fit for big tyres.The installed self protection ... device automatically cuts off if the motor is overloaded.It can infalte bus, truck, van , car ... tyre within 1.5 minutes. It is Water Proof.For car tire , balloon , air bed , water bed . ...