The McAlpine Waste Valve 1.1/2" Uni Macvalve-2 is a plumbing fitting that is designed to control the flow of waste water from a sink or basin. The "Uni Macvalve-2" in the description refers to the specific model of the waste valve, which is manufactured by McAlpine, a UK-based company that specializes in plumbing and drainage products. The waste valve has a 1.1/2 inch inlet that is designed to be connected to the waste pipe from the sink or basin, and a valve mechanism that can be opened or closed to control the flow of waste water. The waste valve is designed to prevent foul odours and gases from entering the room by creating a water trap that seals the waste pipe. Overall, this type of waste valve is commonly used in plumbing applications where a sink or basin needs to be connected to a waste pipe. The McAlpine Waste Valve 1.1/2" Uni Macvalve-2 is made from high-quality materials and is designed to provide reliable performance over an extended period of time. ・ Available in 1¼" and 1½" sizes ・ BSP female inlet nut x universal compression outlet ・ Membrane opens under water pressure to allow discharge to flow freely and then closes to form a seal to prevent foul odour or sewer gas entering the building ・ Can be fitted in horizontal or vertical position ・ Can be fitted in installation where a non-return valve can be of benefit to the plumbing installation