The Unitas 6306 watch movement was produced between 1937 and 1970, with over 3.5 million units manufactured during this period. It featured various chrono mechanisms, and due to interchangable parts, there were instances where series included components from different calibres. The Unitas 6306 had minor differences from the 352, but modified parts could be interchanged between the two. Its functions included a manual-wind chronograph with 60-second, 30-minute, and 12-hour cam switched measurements, as well as a sub-second display.