Cold-X Expansion pipe is cross-linked polyethylene tubing designed for use within potable water piping systems. Produced using a Peroxide method, Cold-X Expansion PEX is PEX-A pipe. Having been in use for over 50 years PEX-A pipe has the highest rate of cross-linking of any PEX pipe. Cold-X Expansion PEX is the most flexible PEX pipe available and provides superior durability, corrosion resistance and flexibility for the most demanding environments. The Cold-X Expansion PEX 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.