This is a lead free Supply Giant Union for connecting, or extending, pipes in applications with a maximum pressure of 125 lb. In particular, this fitting is made of Copper with sweat connects of 1-1/4" in diameter, for use with Copper pipe with an outer diameter of 1-3/8". furthermore, UL/ULC and FM approved the design, which conforms to the ansi/asme B16.4 standard. Additionally, the fitting is produced in an ISO9001:2000 manufacturing environment, and is pressure tested before leaving the facility. The biggest advantage of using a Union, over a coupling, is that the two pipes that are connected can be easily separated because of, for example, Replacement or maintenance. ⚠ California Proposition 65 Warning: This product is known to the state of California to cause cancer, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.