Home » Valves & Fittings » Vent Valves/Ball FloatsModel V421 - Vent Valve AssemblyThe 37 when used in conjunction with the V421 Vent Valve, protects against overfill of the UST. Signals the tranport driver when the tank is filled to 90% capacity, in accordance with current EPA guidelines.Sales SheetPrice: $0.00 V421 Please Select...-0020 -2020 -0030 -3020 -3030 Tweet« Previous | Next »