The ExpansionPEX 1/2 in. PEX-A Expansion Sleeve (25-Pack) is simple to install. ExpansionPEX is produced using PEX-A material. ExpansionPEX is required to create a secure ExpansionPEX connection. ExpansionPEX Expansion Sleeves are engineered with a bevel along the leading edge to ease pipe insertion and an integrated stop to ensure proper placement of the sleeve. The ExpansionPEX 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.