Green/yellow/red system indicate level of proper tire inflation. Green shows that tire pressure is normal. Yellow shows that the pressure is down about 5 pounds. Red alerts you that the pressure is down by at least 10 pounds. Pressure: 2.4PSI.,applicable to car,motorcycle,bicycle and so on. Car tire pressure monitor valve caps help to avoid premature tire wear or blowouts from under-inflated tires,extends tire life. Fit on any standard size existing tire valve stem. Features: Condition: 100% Brand New and High Quality ! Tire Pressure Monitor Valve Stem Cap Sensor Indicator 3 Color Eye Alert New Pressure: 2.4PSI Fit on any standard size existing tire valve stem Visually alerts you when the tire pressure is low to help avoid premature tire wear or blowouts from under-inflated tires Indication: Green shows that tire pressure is normal. Yellow shows that the pressure is down about 5 pounds. Red alerts you that the pressure is down by at least 10 pounds. Specification: Material:Plastic Package weight:28g Package size:5cm*5cm*2cm Color:as shown Please allow 1-3 CM differs due to manual measurement. Package List: 4 X Tire Pressure Monitor Valve Stem