Matthews Studio Equipment 5/8" Snap-in Pin for Mafer and Super Mafer Clamps, Part No. 209632:
The pin pictured with the Mafer Clamp has a hex head that snugly into the Mafer socket. The working end of the pin fits all Baby lights, 2.5" grip heads, or any item with a 5/8" receptacle.
WARNING: This product may expose you to chemicals which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.