1940s Longines Cal.13zn Flyback Chronograph Ref.3870 Rare 3piece Water-resistant Case with Black dial

This is a very rare 34mm 3 piece case waterproof flyback chronograph with black dial, manufactured in the early 1940's, with Longines famous Cal.13zn Ref.3870. This is a rare piece produced during the transitional period when they were experimenting with waterproof chronographs with a very rare 3-piece waterproof case consisting of bezel, middle case and back. 34mm size step case, small round buttons and round shaped back cover, its unique design and size are Unlike the Mushroom, Tretake, 35mm snap water resistance and Lipp, this is a gem of a watch that, despite its modest size, has a massive construction that is unique to Longines, and the precious black dial enchants with its great taste. The Longines in-house caliber chronograph is a perfectly established masterpiece in the history of watchmaking and will continue to be appreciated and handed down in the future. The archive is included.