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 2 color coordinated crimp rings - the included BLACK crimp ring is intended for PEX while the copper-colored crimp ring is for use on Polybutylene pipe.