External Air Admittance ValveThe FloPlast External Air Admittance Valve is designed to allow air into a sanitary pipework system without allowing foul gases to escape into the environment, it prevents the loss of water from trap seals caused by induced siphonage and serves as an early warning indicator for potential blockages. Ideal for external installation, it removes the need to penetrate the buildings roof, offering improved aesthetics and easier maintenance access. Key