Both OEM Williams and Data East power supplies utilized a wired pigtail to connect GI power through the power supply and the master GI relay.  Overtime, these wires and connectors, due to the heat associated with the current flowing through them, deteriorated, became brittle, and needed to be replaced.  During that process, the wires became shorter and shorter, and sometimes wire nuts were even used to get the extension.  The XP-WMSGI-EXT cable provides a 6 inch extension with both male and female ends to alleviate the length losses.