The COLD-X poly PEX-A barb plug is simple to install. COLD-X poly alloy fittings are the perfect alternative to brass in regions where water quality can negative affect brass. COLD-X barb fittings are a key component of the most economical potable water piping systems. Also capable of integration into hydronic heating systems, COLD-X fittings must be secured into place using a COLD-X expansion rings or comparable cold expansion-type sleeve or ring (all sold separately). The COLD-X system is a comprehensive cold expansion 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.