The device had been recently introduced at the time of the novel On Her Majesty's Secret Service and was carried by all Secret Intelligence Service officers attached to Headquarters. The syncraphone was a light plastic radio receiver about the size of a pocket watch, which could be used to communicate with SIS officers within a range of ten miles of their London Headquarters. When the device bleeped, it was the officer's duty to go at once to the nearest telephone and contact his office.