Watchman's Quartz Tell tale Clock by Isgus

Metal. Case size approx 5" diam x 2.8" high. Dial 1.8" diam.

High quality quartz movement. Made by Isgus, Germany. A special numbered key is kept at each point on a watchmans round . This is inserted and turned to print the key number and the time on paper tape. There is a mechanism to detect fraudulent interference