The Longines 37.9ABC is a mechanical watch movement that incorporates several key functions. It features a sweep seconds hand, which provides a continuous motion for increased accuracy. Additionally, it is equipped with an automatic winding system, enabling self-winding functionality. The movement also includes KIF shock protection, which enhances its durability and resistance to external forces. Furthermore, the Longines 37.9ABC movement incorporates a calendar function, allowing for the display of the date.