Integral 1 1/2" multi-fit tee. McAlpine VP3 Air Admittance Valve in White. The McAlpine VP3 Ventapipe 25 Air Admittance Valve is a plumbing product used for venting waste pipes in a buildings drainage system. The valve features an integral 1½" multifit tee, which makes it easy to connect to waste pipes.The valve is designed to allow air to enter the waste pipe system, which helps to prevent the siphoning of water from trap seals and the buildup of negative pressure in the pipes. The multifit tee allows for easy installation onto a 1½" waste pipe, making it a convenient solution for both new installations and retrofits.The McAlpine VP3 Ventapipe 25 Air Admittance Valve has a compact design and can be installed in tight spaces where traditional vent pipes cannot be installed. It is also maintenance-free, which means that there is no need for periodic cleaning or servicing.Overall, the McAlpine VP3 Ventapipe 25 Air Admittance Valve with integral 1½" Multifit Tee is a reliable and easy-to-install solution for venting waste pipes in residential and commercial buildings.・ 1½" Multifit Tee・ Air flow capacity of 4.5 l/s・ For full information on Air Admittance Valves please see below.