A "Turtle DeLuxe" today, made for Portland, Oregon jeweler, Zell Brothers by Movado, circa late 1930s. The watch uses a Taubert et Fils "waterproof" stainless steel case with decagonal screw-down case back....a game changing innovation in "waterproof" case design which Taubert introduced in the mid 1920s.
Zell Brothers also sold other Turtle branded "waterproof" models manufactured by Rolex, such as the "Turtle Timer" and "Turtle Everest".