This is the best way to monitor your car tire air pressure just by looking at the color change of the sensoron the valve. Very popular tool now among motor enthusiasts to keep the steadyair pressure for tire long life and to avoid any accidents that can occur athigh speed due to low and uneven air pressure. This is a 24 x 7 monitoringsystem for you with the visual aid. Indication: Stylishand high qualityFiton any standard size existing tire valve stemVisuallyalerts you when the tire pressure is low to help avoid premature tire wear orblowouts from under-inflated tiresMaterial: Chromed MetalRoundStyle: 36 PSI (2.4 bar)Color: As the picture showItemsize: 23*10 mmNetweight: 22 gmIndication: Greenshows that tire pressure is normal. Yellowshows that the pressure is down about 5 pounds. Redalerts you that the pressure is down by at least 10 pounds. Installation: Determinethe correct tire pressure for your tires. Inflatetire to correct pressure. Install. This new pressure cap tight. Simplylook at the color to know if your tire is low or normalPackage content: 4 x Tire Pressure Indicator Valve Stem Caps.