About this item Instructions for use: 1. First open the upper and lower hooks, and then put it on the ground, set the clip on the car's gas nozzle. 2. Put your feet on the pedals and step up and down in the middle. 3. The first time you finish inflating, write down the location of the pressure gauge pointer for the late inflatable reference. 4. Often add 2-3 drops of oil to the gas cap hole to extend the piston life. 5. This pressure gauge is not a professional one, so that the data may be not exact; the result is only for your reference.