Rolex Bubble Back watch. Stainless steel and 18kt yellow gold. Silver dial with dotted numerals, fiulé hands, 9 3/4"" movement. Leather strap, pin buckle. Automatic movement.Measurements: 32mm (case).At the end of the 1920s, there was a desire to create an automatic movement in watches. In 1931 the autorrotor was created, the rounded back of the Bubble was designed to make room for the automatic rotor, thus, in these models we can appreciate a mixture of the lines of the art-déco movement combined with pure and elegant forms. In Italy, they are known as "ovetto" or little egg, and are also highly appreciated in the Japanese market, for their purity and elegance, while at the same time marking great sobriety.