These are for deep threaded valve stems only. They will not seal regular size valves. They thread on nicely and do the job of a regular valve cap, but unless you have a deeper thread they won't seal. I had to cut off 1/8 inch for it to seal. Also, I found that the thread tolerance and internal diameter are larger and it's not a tight fit. I'm sure this will be done to accommodate valves of different sizes and threads around the world. Anyway, that's my opinion, or they're just cheaply made.