This Pneumatic Self-Timer is a neat and uncommon accessory made in the Soviet Union in the 50's and 60's.
The unit consist of a cylinder with a spring-loaded piston, which drives a
release pin. The cylinder has a valve on the top which controls the vacuum in
the cylinder. You simply screw the self-timer in the cable release thread on
the camera, arm it, and release the piston. The spring will drive the pin down,
overcoming the vacuum in the cylinder. By opening and closing the valve you
can set the delay time. At the end on the movement, the pin "shoots" with great
speed and force, and this may possibly shake the camera. I do not know how useful
the gadget is, but it is surely working well, made nicely, and is quite uncommon.
The self-timer comes in a plastic case.