How-To Activate Glow-in-Dark Dial Step 1... Expose dial face directly to any bright ambient light source for a minimum of ten seconds. * Common sources: flashlight app, interior light, headlight, sun, tire inflator light, etc. Step 2... See for yourself Dial will remain illuminated for five to ten minutes for easy use in low light conditions Easy to Use and Quickly Deflate Screw off the valve caps first, then simply twist the air chuck on the valve stem and unscrew the valve core. Pull the slide -valve to air down while push the slide-valve to check the pressure. With the deflator, we can remove the valve core safely and keep the air down in a high speed . Accurately Mechianical Tire Air Gauge Bourden tube mechanism and no batteries required., Legible 2" Glow-In-Dark Scale,Presure range from 0 to 75psi and 0 to 5barDual scale with English and Metric, easy to read for different people. Accuracy certified with ANSI Grade B40.1 Grade B. Keeping a Good Performance for Years Heavy Duty structure Durable Components Suitable for all vehicles with schrader valves.Consits of solidly corrosion resistant Brass deflator, strong braided air hose and gauge with a rugged gear-style rubber protector, rugged tire-style rubber protector,built to last Ergonomic and Compact Design Tire Air gauge with smart shape and size fits your hand for ultimate comfort and control. Put in the red pocket and easy storage in the car