The normal position of the tire pressure indication is generally 2.2 pressure, no more than 2.5, about 35 PSI, and should not be deceived by the so-called 300 psi. Product features: Zinc alloy hand gun body, strong and durable Suitable for all kinds of small and medium passenger vans, cars, motorcycles, etc. It has the function of deflating, inflating and testing vehicle tires, and can also be connected to an air pump. It has functions such as blowing ash on the car engine. Measurement data, intuitive, fast, conversion unit PSI, bar, Measurement range 0 - 220psi; 0 - 16 Bar Instructions for use 1. Unscrew the valve chamber cover from the tire. 2. Press and hold the pressure gauge air hose bow, Align it with the inserted tire valve, Align it with the bow the bow is attached to, then release the bow. Note: It is recommended to maintain pressure with one hand to avoid air leaks. 3. The tire pressure gauge will show the tire pressure. The red font for the inner circle is kilogram square centimeter and the black font for the outer circle is square inch pound. 4. Please inflate if the tire pressure is not enough. If the tire pressure is too high, press the deflation valve and adjust the pressure accurately. 5. After the measurement is completed, hold down the clamp, press the deflation valve to zero the pressure gauge needle, and tighten the tire valve cap.