The SharkBite PEX Poly Alloy Barb Coupling is an easy to install, low-cost solution to connect to PEX tubing. This fitting allows you to transition pipe size with one fitting. These fittings are suitable for potable water distribution and hydronic heating applications. SharkBite PEX Poly Alloy Barb fittings can be used in both a stainless steel clamp system, or a copper crimp ring system as well (each sold separately). Approvals: ASTM F2159, NSF/ANSI 61, NSF 372.