This is a #3 shutter with 61mm openings front and rear. It has three scales: starting at f18, f12.5 and f6.8.
The speeds go from 1 to 50. The aperture has many many blades.
All of the shutter speeds are strong and accurate except at 1/5, which seems to be performing too fast. It seems to fire at around 1/25.
It comes with the lock ring.