The McAlpine VP100N Ventapipe 100 Air Admittance Valve is a plumbing device designed to allow air into the drainage system while preventing foul odors from escaping. Suitable for use with a 4"/110mm soil pipe, it features a solvent weld outlet for a strong and permanent bond when connected with solvent cement. Manufactured by McAlpine, a trusted name in plumbing, this valve meets high standards of quality and reliability. It is A1 rated and has an air flow capacity of 19.4 l/s. The Ventapipe air admittance valve enables venting for soil and ventilating stacks without the need for holes through the roof or external walls. It incorporates a sealing diaphragm that is normally held closed, sealing foul air within the pipework.