CONBRACO PEX - poly-alloy insert fitting type a plug - PEX a plug poly alloy. Used to permanently or temporarily cap off the ends of the PEX tubing for purposes such as pressure testing. They can also be used to prevent dirt, dust and debris from entering the open ends of PEX tubing during construction. For use with cold expansion PEX a pipe and sleeve system. Compatible with upon or (wirsbo) piping systems ( is a trademark of upon or). ASTM F1960. - type: plug, size: 1 in., material: poly-alloy, PKG quantity: 10, package type: bag.