B&K 1/2" Rubber Washer for Dielectric Union is designed as a rubber washer specifically made for dielectric unions. Crafted from durable black Buna-N rubber, this washer excellent resistance to various fluids, ensuring long-lasting performance. Dielectric unions serve to connect pipes made from different metals, preventing galvanic corrosion, and this rubber washer plays a crucial role in creating a tight, leak- seal within the union. By using this washer, you maintain the effectiveness of the dielectric union in protecting your piping system from corrosion and leaks. Model Number: 888-239