The watch pictured was most likely produced in the 1920s. It appears to be either a hinged styled case (back opens on a hinge like a door) or a three piece case (movement is accessed by separating case back from crystal housing. These watches featured mostly .925 sterling cases often accented with gold fill outer shell to give gold appearance. The watch looks to be one of the very early Oyster models that were some of the first "waterproof" wrist watches. This attached 1929 ad shows similar models. Enjoy the watch!