The Waterway 417-5130 union tailpiece is designed for compatible plumbing applications using a 2 inch flange connection and a 1-1/2 inch female pipe thread nut tailpiece configuration. This setup is useful where the union side must tie into a smaller female-threaded plumbing path while preserving compatibility at the flange side of the assembly.That size and connection-style change makes this Waterway tailpiece especially practical in retrofit work where the original equipment and downstream plumbing do not align one-to-one. Using a purpose-built tailpiece helps keep the connection cleaner and easier to service.For compatible plumbing service and union replacement work, this Waterway tailpiece is a practical option when a 2 inch flange must transition into a 1-1/2 inch female-threaded connection. Waterway union tailpiece 2 inch flange x 1-1/2 inch female pipe thread nut tailpiece Useful for serviceable size and thread-style transitions Helps support cleaner retrofit plumbing Maintains union compatibility at the connection point