PVC inserts for 17" Hummer Wheels. Inserts go inside your tire and allow you to air down and run low air pressure with the Hummer Double Bead Lock Wheel. With the PVC insert installed (inside the tire) both inside and outside beads are pinched between the insert and the wheel making them double bead locks. Run flats went inside the tires and served 2 purposes. They made the wheel a double bead lock while at the same time allowed the Humvee to take a bullet at war and have the tire maintain it’s original height so the soldier could drive out of combat. This is great while at war but not when you want to air down to wheel. The run flats will tear up the inside of your tires over time. There are a lot of people that cut the stock run flats down (cut the profile off of them). This is where the PVC inserts comes into play. It makes the wheel a double bead lock without the profile of a stock run flat.