The Leica IIIg is the last thread mount Leica, released in 1957- that's a good three years after the much more modern M3. The IIIg still has separate rangefinder and viewfinder windows, but the viewfinder is substantially improved, with a larger view and projected framelines- definitely the best of the thread mount series. This IIIg is in really excellent condition, with minor wear and brightmarking on the bottom plate. Film tested, and I won't leave you in suspense: it works great. A beautiful camera that you should buy before I do.