The NIBCO INC 21617153 is a 1/2 x 4-inch long stem extension made from durable PVC, designed for use in various plumbing applications. This extension is ideal for reaching difficult areas or providing additional length in piping systems. With a lightweight yet sturdy construction, it ensures easy handling and installation. The PVC material offers excellent resistance to corrosion and chemicals, making it suitable for both residential and commercial use. This stem extension is compatible with a range of NIBCO fittings, ensuring versatility in your plumbing projects.