THIS IS THE MARCONI MARINE ' SEAGUARD ' - A MECHANICAL WATCH KEEPING RECEIVER, IT RECOGNISED THE CW ALARM SIGNAL I.E TWELVE , FOUR SECOND DASHES SEPARATED  BY A ONE SECOND SPACE ALL SENT WITHIN A MINUTE , EITHER BY HAND KEY OR PREFERABLY BY THE AUTO ALARM SENDER. SHAW SAVILL & ALBION'S CANOPIC HAD ONE OF THESE AS PICTURED ABOVE I.E THE UPRIGHT VERSION. THE BENHIANT / CRAMMOND HAD A RACK MOUNTED VERSION. THERE WAS ANOTHER MODEL WHICH WAS A STAND ALONE VERSION AS FITTED TO SHAW SAVILL & ALBION'S 'MEDIC'