The Cyma Tavannes 999 is a mechanical watch movement with a Breguet hairspring. It features several functions including a timer rattrapante with a precision of 60 seconds (0.2 seconds) and a duration of 30 minutes. The movement has a pillar wheel mechanism for smooth operation. It is a stem wind movement with a split second function, controlled by a pusher located at 11 o'clock. Additionally, it includes a subsecond display and a chronograph function.