Features: Visually alerts you when the tire preure is low to help avoid premature tire wear or blowouts from under-inflated tires. Enhances road handling, increases economy, extends tire life . New generation copper core design, better quality with bra core, with anti-theft function. Green/yellow/red system indicates level of proper tire inflation . Increases fuel efficiency, safety and control . For use on 36 pound per square inch recommended preure . Simply install on the air valve . Description:Specifications: Material: Chromed Metal + Bra core Size:2.2*1cm Weight:32g Color: silver Package included : 4 pcs * Tire Preure Indicator Valve Stem Caps Notes: Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. Please allow slight dimension difference due to different manual measurement.