Sure Vent Air Admittance Valve Kit, 6 DFU With Tubular Adapter, Air Admittance Valves Provide An Alternative To Secondary Venting When Utilized Within The Scope Of Model Plumbing Codes, Referenced Standards & Installation Instructions, AAVS Provide The Ideal Venting Solution For Island Sinks, Remote Bathroom, Includes 1 Valve & Necessary Tubular Pieces.