Slime is a great way to fix a flat tire before damaging the rim. It's easy to use thanks to the dual function cap that unscrews the valve stem and also seals the empty bottle so you don't make a mess in the car. A transparent tube built into the side of the bottle creates a tight seal around the valve stem, virtually eliminating fluid leakage into the tire. I bought them for my mom and grandma as well as mini air compressors. The slime can seal larger holes than the glass to repair the plane, allowing them to reach their goal no matter the situation. * Make sure you pull forward to bring the valve stem down.