Apollo expansion PEX female adapters are manufactured using lead-free dezincification resistant brass. Exclusively designed for use with PEX-A pipe, the fittings offer a larger ID than traditional crimp fittings for full flow resulting in fast delivery of potable water. For use with PEX-A pipe only. Suitable for use in hot and cold domestic potable water and hydronic heating and cooling piping systems. Compatible with Uponor (Wirsbo) ProPEXâ„¢ piping systems. ProPEXÂ® is a trademark of Uponor.