Nikon MB-D15  type_Accessories It has individual locks for

It has individual locks for panning and ball operation

The Olympus M

Canon TTL Hot Shoe Adapter 3 for off-camera TTL flash control using Canon’s corded off-camera TTL accessories

Honestly seems like a lot of engineering and manufacturing complexity for not a lot of payoff

Protective filter

Nikon MB-D15 &nbsptype_Accessories It has individual locks forThe Nikon MB D15 is a vertical grip and battery holder for the Nikon D7100. It accommodates an extra EN EL3e battery with the included tray, or with appropriate carriers (not included) it'll take an EN EL4a or 6 AA batteries. This MB D15 is in very good cosmetic condition, with minor wear from normal use and handling.