The Certina 19-251 watch movement is an open face calibre with a pin-lever escapement. It features a coarse imitation of balance screws and an early two-section regulator for coarse and fine adjustment. The movement stands out for its ratchet under the base plate and a crown mechanism with a rocker bar. It was previously designated as 13-43 but is now referred to simply as 43. It offers functions such as stem wind and pin set, sub second, and was commonly used around 1920.