Come and see our amazing products. Car tire pressure monitor valve caps help to avoid premature tire wear or blowouts from under-inflated tires, increases fuel efficiency, safety, and control, extend tire life. The green/yellow/red system indicates the level of proper tire inflation. According to 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. Pls confirm further with us if any query about packing info, inventory status and time schedule.