Car tire pressure monitor valve caps help to avoid premature tire wear or blowouts from under-inflated tires,increases fuel efficiency, safety and control, extends tire life Green/yellow/red system indicate level of proper tire inflation.According the recognize color to display the pressure of the tire,Green shows that tire pressure is normal Yellow shows that the pressure is 10% lower than standard Red alerts you that the pressure is 25% lower than standard Fit for 32-36PSI(2.2-2.4Bar),applicable to car,motorcycle,bicycle and so on.WARNING: When removing a cap. make sure that you do not lose the black washer. They are inclined to fall out and are very difficult to find again. It is advisable to remove them before your car is serviced at a garage. Material of car tire pressure indicator caps: Chromed Metal+PC;Size:1cmX2.5cm;Visually alerts you when the tire pressure is low Package : 4 x Tire Pressure Indicator Valve Stem Caps Why Choose us? 1. A tremendous variety of products-- With over 2,000 items in stock, Kasa is currently being one of the world's largest online stores. You'll have more choices than what you can ever imagine. What's more, we're updating with over 50 new arrivals per day! 2. Affordable prices -- Kasa is being offering the latest car parts and accessories for almost 10 years, we're always keeping up with the newest trends, while most importantly, making the prices as low as we can. 3. No-question