Poor design can't leave the valve when changing a tire, once you start screwing it on let the air out - there should be more threads for it to be left in can that the valves can not be removed through the bracket and balance and back into the car, also too heavy, if you balance the wheels, the balance will be disturbed, and the position marks on the heads will be too small. great idea but needs work to be useful in the real world. use the store.