The Marvin 565 watch movement, also known as the hunter calibre, features a Breguet hairspring and early samples may include a bimetallic screw balance. It should be noted that there are no known differences between the 527, 535, and 541 variations, except for varying bridge layouts. This movement is characterized by its stem wind and set function, along with a sub second display. It was commonly used during the period of approximately 1930.