An expander head for the Wirsbo Expander Tool is meant to be inserted into PEX Tubing to allow it to stretch out in order to allow a fitting inside. A 1" PEX fitting will not fit into a 1" PEX Tube unless the tube is expanded using a Wirsbo Expander Tool.
PEX Tools, PEX Fittings and PEX Tubing can be found at www.supplyhouse.com
