Legend 461-949 .75" CE PEX x MNPT Plastic Adapter. These fittings are intended for use in cold- and hot-water distribution (potable) systems. An ideal high-strength corrosion-free alternative to metallic fittings. Barbed end connections are designed for use with PEX (ASTM F 876 & 877) and PE-RT (ASTM F 2769). Designed for use with cold expansion rings that are manufactured in compliance with ASTM F1960.