The Edelbrock Purge Valve Kit keeps the supply of fresh liquid nitrous at the solenoid for instant and repeatable nitrous injection. It is designed to vent gaseous nitrous to the atmosphere to fill the nitrous feed line with liquid nitrous for a better nitrous charge when the nitrous system in use. This purge kit bleeds accumulated nitrous vapor from the supply lines. The size of the hose is 4 AN (Anodized) and it includes solenoid, activation switch, filter, aircraft-quality fittings and wiring.