Car Tire Pressure Gauge Digital Tester LCD Display Multifunctional High Precision Auto Repair Maintenance Item Type: Tire Pressure Gauge Material: Rubber + Brass Gauge of Diameter: Approx. 57mm/2.2in Battery Type: Built-in Button Battery Battery Model: CR2025 Nominal Battery Capacity: 150mAh Pressure Range: 0-200psi Fitment: Universal How e: 1. Unscrew the tire valve. 2. Fix the copper head of the instrument to the valve. 3. The device will display the pressure. 4. You need to find the air pump (not included) and the air tube (not included) to connect the air nozzle, and hold the handle of the tire pressure gauge to inflate it through the inflator when the pressure is low, and vice versa. 5. After the measurement, unscrew the copper head and press the vent button to make the indicator change to 0.