Roll over valves allow air into the tank to replace the fuel being used, air out of the tank due to heat expansion and a positive shut-off to prevent fuel escape due to the vehicle rolling over. These are made from billet aluminium and anodised to protect it. It has a ball bearing inside the bottom half, allowing air to breathe easily without restriction. However, if the tank is turned upside down, the ball bearing drops to the top of the fitting, effectively cutting off the exit. These bolt-in rollover valves are designed to be installed into a fuel tank or cell as a bulkhead-style fitting. Available with -6 to -16 AN fittings and comes with two Teflon Washers for sealing.