I liked these when they arrived and attached them to my car but a few months later I was having to pump up tires and couldn't get them off my valve stems. They're metal and welded directly to the valve stems, so I had to have all the valve stems replaced with a tire changer, which isn't cheap. Do yourself a favor and don't use them, or if you have to take them off and on once a week to break the bond before it becomes permanent.