Nitrous Express NHRA Safety Blow-Off (3000 PSI) Fits All NX Valves w/Female ThreadsNHRA rules require the safety blow off to be routed outside the vehicle. This fitting replaces the existing safety blow off fitting and allows you to attach a blow down tube to the safety blow off fitting. Fits lightning 45 bottle valve and NX chrome bottle valves with female threads. Disk not included. For chrome valves, use with a new disk (part# 11712). When used with a lightning 45 valve (black), reuse the existing disk in the valve.