The Imhoff 312 watch movement is an open face calibre with the pendant mounted on the movement. It features a pillar wheel with functions including a 60-second, 30-minute chronograph, as well as options for a 30-second, 15-minute chronograph and a 10-second, 5-minute chronograph. The movement also includes a center second hand and a timer function. It was used during the period of approximately 1970.