1.1 ,This specification establishes requirements for sulfone plastic insert fittings and copper crimp rings for three sizes (¹/₂ ,, ³/₄ ,, and 1) of cross-linked polyethylene (PEX) tubing that meet the requirements for Specification F876 or F3253, and polyethylene of raised temperature (PE-RT) tubing that meet the requirements of Specification F2623. These fittings are intended for use in 100 psi (690 kPa) cold- and hot-water distribution systems operating at temperatures up to and including 180 ,°,F (82 ,°,C). Included are the requirements for material, molded part properties, performance, workmanship, dimensions, and markings to be used on the fittings and rings.