XFITTING PEX Compatible with all types and brands of PEX Tubing - Watts, Everhot, Viega, Zurn, Nibco, Bow, etc. Design certified to ANSI/NSF-61 and ASSE 1061 product standard for use in potable water and hydronic heating water distribution. Work with Crimp Connection System (PEX Crimp tool + Copper Crimp Rings) or Clamp Connection System (PEX Clamp tool + Stainless Steel PEX Clamps) 400 PSI, Approved to be used underground and behind walls without access panels