Antique Gauthier Ibso shutter, with a German C P Goerz Series III Dagor 150mm 1:6.8 lens.  In need of some attention – the shutter fires fine on 100 and 50 speeds, but the iris blades tend to stick on slower settings, so may need some lubrication.  The aperture works.  The optics do have some heavy dust fragmentation internally, so would benefit from a clean, but appear relatively fungus free.  There is some paint loss, plus a small hole to the rear mounting, just under the thread.  The thread mounting would be about 34mm in diameter.  It comes with card lens caps.