Many things depend on tire pressure. This includes fuel consumption, traction, braking performance and much more. In order not to run around the car with a pressure gauge every time, but at the same time to be sure of the level of pressure in the wheels, you can install special caps on the nipples. Caps have color indication, which shows the state of pressure: normal, below normal and critical pressure. Suitable for all cars. There are 4 caps in the set.