Paillard Bolex H16 or H8 Trigger Handle Pistol Grip
The Paillard Bolex trigger handle was available by 1950 for the Bolex H camera. It attaches to the tripod socket of the camera, and allows the release button to be operated from a trigger lever on the grip.
This has a 3/8″ mount screw.
Good condition with just minor marks from previous use.