FIELD: protection of premises using additional tools for stock-produced locks. SUBSTANCE: device has moving plate and moving rest for the plate. Plate is spring-loaded and is located in housing so that one end of plate can enter into key hole, for example, of cylindrical mechanism of lock. Housing of plate is stationary mounted with respect to key hole. Plate rest is designed as similar spring-loaded plate which is mounted for longitudinal movement in plane of stationary base. Ends of both plates are located in opposite and have mechanic hooks. One end is also spring-loaded in cross direction. Alarm signal is generated when picklock or master key is removed from lock in case if lock has not been opened by either picklock or master key. EFFECT: increased protection. 15 cl, 1 dwg
