New, Apollo ExpansionPEX is cross-linked polyethylene tubing designed for use within potable water piping systems. Produced using a Peroxide method, Apollo ExpansionPEX 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. Apollo ExpansionPEX is the most flexible PEX pipe available. Apollo ExpansionPEX Pipe provides superior durability, corrosion resistance and flexibility for the most demanding environments.. Make an offer!;