Ercole M11-050A Umbrella Swivel Adapter with brass stud

Due to its spring loaded clamping, this cold shoe clamp enables one to one-handedly mount shoe fitted equipment very easily. Its finger screw serves both as a push knob for opening the clamp and for tightening down the clamping securely.
It fits the standard shoe sizes of 18, 20 and 22mm.
The Cold Shoe Clamp is tapped with 1/4″-20 and 3/8″-16 holes on the back side

Manfrotto 155 Head Double Ball w/ 143 14.5cm. 2x 16mm studs with Camera/Umbrella Bracket.

Ultralight AC-CSB ball clamp with black knob for large buoyancy arms