This is great! I have 3 quads, 2 side by side, a buggy, a tractor and 2 trailers. I got tired of some tires "losing air" but a couple of times I found it was the valve stem. When you fill the tires with air, they sometimes stick or get dirty and leak slowly. A local tire shop gave me some of these metal valve caps, they have a rubber o-ring inside and they seal even if the valve core is leaking and you can check tire pressure or pump air with these metal valve caps and they don't You don't have to take the cap off and then put it back on every time you check or add air like with "regular" valve stems, they just screw on, just like valve stem caps. I have 26 of these on almost anything that moves, never had a "leak" again, it's fantastic!