The part is made by Rockwell Automation and is PN 1492-CJJ12-4. You can find a local distributor at
http://www.rockwellautomation.com/distributor. It was about 70 cents from our distributor.
This information and suppliers for most of the kit parts is in the "Tips and Good Practices" document available here:
http://www.usfirst.org/WorkArea/link...id&ItemID=4054