Copal No1 press shutter for large format photography with rear retaining ring. Sold as repair or spares: shutter is usually slow to open, click it a few times and it speeds up and then is OK (possibly a lubrication issue ?). Speeds T, B, 1 to 1/125, f45 to f4.5. Lens fitted is Tominon 1:4.5 75mm: but really it is the shutter that I am selling.

Originally designed for press photographers who needed to shoot quickly, they feature two unique advantages versus the conventional "cock and release" Copal shutters supplied with large format lenses: they are always cocked (because the act of firing the shutter readies the springs for another exposure), and the shutter can be quickly opened to its maximum aperture.