You are looking at a vintage boxed Gauthier Prontor-Matic 125 531bf Shutter

It has speeds between 1/30 & 1/125 and a B setting. Aperture scale is between 2.8 and 22

The outside rear thread is about 24.5mm, inside rear thread is about 21mm and the inside front thread is about 22mm.

The shutter looks in good cosmetic condition with little wear.

Speed setting moves smoothly and the shutter fires fine on all speeds and B.

Aperture setting is also smooth and does its job. Blades are in good order and free from oil deposits.

The photos form part of the description so please study carefully

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