This is an upgrade to replace the previous mounting pin on our version 1 Focus Mount products. This part now comes standard with our Focus Mount PRO and Focus Mount PRO XL.   This is a machined part that is much stronger than the diecast pin that came with the original Focus Mount.  Machined from 6061 aluminum, it will mount onto both a Junior Socket (1-1/8", 28mm) from a Combo or Junior Stand, as well as onto a standard Baby Pin (5/8", 16mm) from a C-Stand or Baby Stand. It includes the two screws needed for mounting as well as the tightening thumb screw handle.  This will replace the pin on both the Manfrotto and Impact brand pivoting boom clamp products. 
For mounting instructions see link here.