The McAlpine S12D is a 1" BSP (British Standard Pipe) female to male coupling. It is a plumbing fitting that is commonly used to join two pipes or fittings with male and female threads together. The S12D coupling is made from high-quality materials to ensure it is durable and long-lasting. It has a female BSP thread on one end and a male BSP thread on the other end, making it compatible with a wide range of other BSP fittings. The McAlpine S12D coupling is suitable for use with a range of different liquids and gases, including water, gas, and oil. It is commonly used in commercial and residential plumbing installations and can be used in a variety of different plumbing systems. Overall, the McAlpine S12D 1" BSP female to male coupling is a reliable and durable plumbing fitting that is suitable for a wide range of applications. Its high-quality construction and compatibility with other BSP fittings make it a popular choice among plumbers and DIY enthusiasts alike. ・ Available in 9 sizes ・ Waste Outlet Reducer