In 1923, watchmaker Hans Gilomen reached the point where he founded Onsa AG in order to develop his business, which at that time was still just a typical Swiss family business in the town of Lengnau in the canton of Bern. From 1943, more serious emphasis was placed on brand building and marketing communication, so they seized every opportunity to make the ONSA name known and recognized in the European and overseas watch scene. From 1949, Onsa became the main sponsor of the Bern Grand Prix in the world of motor racing, in 1957, on the occasion of the famous Atlantic crossing of the Mayflower II. the ship was equipped with two Onsa watches, which had to perform flawlessly during the journey in extreme conditions, with the forces of wind and nature; the other had to perform flawlessly under water, deep in the depths. From that same year, the Belgian airline SABENA had Onsa watches ticking on the wrists of all its pilots, and The world-famous Swiss Renaissance man and extreme diver Hannes Keller was also accompanied by an Onsa Scaphandrier when he set the world depth record on the day of his dive in Lago Maggiore in 1960.This rare and very beautiful ONSA Superautomatic "Calendar Moon phase" watch is powered by a FELSA "Bydnator cal693" movement, in an extra 30 jewel version. This movement was used by many famous brands, including Breitling, Vulcain Gubelin and Record. Breitling Datora: One of the most famous models that used the Felsa 693. This automatic, moon phase calendar movement was especially found in the Ref. 84-28 and Ref. 55-28 models.I will be happy to answer all questions and send additional pictures and videos.The advertised price does not include the cost of insured, tracked shipping.I am a collector for many years, where vintage watches represent about 80% of my activity. I always honestly describe the condition of the items offered for sale and I am doing my best to be a trusted seller. I have a long track-record to engage in fair transactions. As a result of my track record, I was also supplying genuine vintage watches as props for Hollywood productions shot in Hungary (e.g., Red Sparrow). IMPORTANT NOTICE Import duties, taxes and charges are not included in the item price or shipping charges. These charges are the buyer's responsibility. Please check with your country's customs office to determine what these additional costs will be prior to bidding/buying. I answer your questions as soon as possible.