Reference 3055 was originally launched in the 1930s, featuring oval-shaped chronograph buttons. With its 10 1/2''' movement it was at the time the smallest chronograph wristwatch ever produced.
The 1950s re-edition, such as the present lot, was made with a Valjoux caliber 69 movement and rectangular chronograph buttons.
The model is described and illustrated in I Cronografi Rolex - La Leggenda, Pucci Papaleo Editore, pp. 108-111.
For a reference 3055 in yellow gold see lot 338 in this sale.