When you need to apply more tire sealant during a trip, such as slipping off a bead or making roadside repairs, this tool is where it's vitally important. This will allow you to remove the valve stem so you can add more sealant. It's tiny and light. I tucked mine into a small zip lock along with an extra main chain link and a few other small bits (that I hope never need on a hike) and stashed them in my hydration pack to keep with me at all times. .