Uponor Wirsbo offers the AQUAPEX® flexible plumbing system. Featuring the crosslinked molecular structure of Wirsbo's Engel Method AQUAPEX tubing (PEX-a), along with the company's ProPEX® fitting system, AQUAPEX offers superior strength and flexibility, plus high temperature and pressure resistance. AQUAPEX is completely corrosion-resistant and non-toxic, eliminating concerns about lead, copper and other metal ions, as well as chemical contaminants. AQUAPEX tubing is NSF 14 and 61 certified, listed to ASTM F876 and F877, approved by CABO, and IPC, and accepted by IAPMO. Uponor Wirsbo. Circle 24.