The pictures I've added show how deep the cap removal pocket is valve stems. I didn't use the end to remove the core. My main goal was access to the inner valve stem of the bike on dual bikes. As you can see from the photos, the pocket is deep and allows the tool to sit fully on top of the lid. The friction closure keeps it in place so I was worried about dirt ruining it. It didn't bother me at all. The fit is so snug that there were no issues. On the first few tires I used it on, I actually had to push and twist to get it to fit completely around the hubcap. The rubber was hard and wouldn't budge until I broke it a little.