This Copal #3 (#3-585) Shutter is a high performance, smaller #3 size manual cocking shutter. This shutter differs from Copal #3 Shutter (3-567), in that it has a slightly smaller mount thread (M61-0.75).
The shutter release lever exposes film or digital sensor after you close the view lever and cock the shutter. Click-stop lever controls shutter speeds from 1 to 1/125 second, plus "Bulb". Flash sync terminal is standard "PC" type. It includes rear retaining rings and basic f/stop calibration instructions for your particular lens.
Note: f/stops are not calibrated, and their positioning depends on the lens that is to be coupled with the shutter.