Omega / Chs. Tissot & Fils, for Udall and Ballou, extremely rare vintage diver wrist watch with patented special form double case polished and satin, delivered to the renowned jeweler ''Udall and Ballou'' in New York, around 1935, Omega Cal. 19, here we have probably the world's first known diver watch, the applied case construction comes from Louis Alix from Geneva, the patent for this from 10.March 1930 from Switzerland, the patented steel case is clamped together by a lever on the back, which creates the water resistance, the sapphire crystal is sealed in the case, the air cushion between the case parts also serves as temperature compensation, the case was mainly used by Omega as model ''Marine'' in the 30's, to further fuel the spread in the market Omega and Tissot joined forces on this watch, both signatures can be found on the movement, champagne color dial with applied silver color dial. Dial with applied silverf. Indizies and arab. numerals, 24,5 x 34,5mm, height 9mm, black leatherstrap with silverf. Buckle, movement with manual winding runs, very good condition, comes from a watchmaker collection liquidation