About the Product:1. Material of car tire preure indicator caps: Chromed Metal+PC;Visually alerts you when the tire preure is low2. Car tire preure monitor valve caps help to avoid premature tire wear or blowouts from under-inflated tires,increases fuel efficiency, safety and control, extends tire life3. Green/yellow/red system indicate level of proper tire inflation.According the recognize color to display the preure of the tire,Green shows that tire preure is normal Yellow shows that the preure is 10% lower than standard Red alerts you that the preure is 25% lower than standard4. 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.3 Noticeable Colors,Easy to view,Save worry and SafeVisually alerts you when the tire preure is low to help avoid premature tire wear or blowouts from under-inflated tires.Green/yellow/red system indicate level of proper tire inflation.According the recognize color to display the preure of the tire.Green shows that tire preure is normal.Yellow shows that the preure is 10% lower than standard about 5 pounds.Red alerts you that the preure is 25% lower than standard at least 10 pounds.Fit for most vehiclesThis item can be used to most of vehicles,such as cart,car,RUV,SUV,Truck and so on.It is a good choice for whome has no TPM Systems on cars.We have three pack for choose:Pack 1: 4Pcs Chromed Metal + Plastic CorePack 2: 4Pcs Chromed Metal + Bra CorePack 3: Anti-theft design - 4Pcs Chromed Metal + Bra Core + Anti-theft wrench