Blow-Down Kit, N2O Blow Down, For internally threaded nitrous bottle safety ports. Includes 82112, 82113, 82115, 82117, 82120 and NS6693., Internal Thread Blow-Down Kit, Safely releases nitrous pressure in the event the bottle becomes over-filled or over-heated. Required by race tracks., Safety Blow Down Kits, Nitrous Oxide Blow Down Tube