The Apollo PEX 3/4 in. Copper Pro Crimp Ring (75-Pack) is simple to install and is designed for use with PEX pipe and barb fittings (not included). Made from copper for durability. Pro Crimp Rings feature an end stop that ensures proper placement of the ring on the pipe end. The end stop also prevents the Pro Crimp Ring from sliding or moving on the pipe prior to being secured. Requires a crimping tool (sold separately). Apollo PEX fasteners are a key component of the most economical potable water piping systems. Also capable of integration into hydronic heating systems, Apollo PEX fasteners can be can be used with brass and plastic fittings, valves, and manifolds (all sold separately). The Apollo PEX system is a comprehensive piping system comprised of brass fittings, poly alloy fittings, manifolds, valves, fasteners, tools and tubing designed for implementation in water delivery systems, simple or complex