The McAlpine ST90CP10-NRV 90mm x Spring Loaded Non-Return Valve with 1½" Solvent Weld Outlet Socket is a plumbing fitting that is designed to prevent backflow of wastewater. The valve features a spring-loaded mechanism that allows water to flow in one direction but prevents it from flowing back in the opposite direction. The valve has a 90mm diameter and a 1½" solvent weld outlet socket, making it compatible with a wide range of plumbing systems. Its overall height is 53mm, which makes it compact and easy to install in tight spaces. One of the key benefits of the McAlpine ST90CP10-NRV valve is its ability to prevent backflow of wastewater. Backflow can occur when there is a sudden change in water pressure, which can cause contaminated water to flow back into the clean water supply. This can pose a health risk, making it important to have a non-return valve installed in your plumbing system. The spring-loaded mechanism in the valve ensures that it operates smoothly and efficiently, even in high-pressure situations. The valve is made from high-quality materials that are designed to withstand the rigors of daily use and to provide long-lasting reliability. Overall, the McAlpine ST90CP10-NRV 90mm x Spring Loaded Non-Return Valve with 1½" Solvent Weld Outlet Socket is a high-quality plumbing fitting that can help to prevent backflow of wastewater and ensure the safety and cleanliness of your plumbing system. Its compact design and easy installation make it a popular choice for both DIY enthusiasts and professional plumbers alike.