The Apollo ExpansionPEX 3/4 in. Brass PEX-A Barb x 1/2 in. Female Pipe Thread Adapter 90 Reducing Drop-Ear Elbow is simple to install and is designed for the installation of tub and shower outlets in most applications. Apollo ExpansionPEX barb fittings are a key component to one of the most economical potable water piping systems. Also capable of integration into hydronic heating systems, Apollo ExpansionPEX couplings must be secured into place Apollo ExpansionPEX sleeves or comparable expansion-type sleeve or ring (all sold separately). The Apollo ExpansionPEX system is a comprehensive piping system comprised of lead free brass fittings, poly alloy fittings, manifolds, valves, fasteners, tools and tubing designed for implementation in water delivery systems, simple or complex. A cold-expansion tool (sold separately) is required for installation.