Product features. 1. Dial size: 2'' 2. Metal construction, sturdy and durable 3. Materials: copper, iron, aluminium, plastic, rubber 4. High quality precision movement for accurate measurement and durability 5. Protective rubber case to protect the product 6. 360 degree rotatable brass head, compact design 7. One-touch deflation device for easy adjustment to the right tire pressure psi, bar and kg/cm2 conversions. Units psi bar kg/cm2 1 psi 1 0.069 0.07 1 bar 14.5 1 1.02 1 kg/cm2 14.2 0.98 1 Procedure for use. Unscrew the cap of the tyre valve. Insert the brass tip of the tyre pressure gauge into the valve and tighten it. The tyre pressure gauge will show the tyre pressure. If the tyre pressure is insufficient, inflate the tyre; if the tyre pressure is too high, press the bleeder valve to vent the air. The normal tyre pressure for small cars is 28psi-35psi. When you have finished measuring, unscrew the brass tip, press the bleeder valve to zero the needle and screw the cap back on the tyre valve.