The SharkBite® PEX barb polybutylene adapter is made of a lead-free DZR brass and is an easy-to-install, low-cost solution to connect PEX tubing to polybutylene pipe. SharkBite® PEX barb fittings are compatible for potable water distribution and hydronic heating applications. This product includes two-colors co-ordinated crimp rings the included black crimp ring is intended for PEX while the copper colored crimp ring is for use on polybutylene pipe.