Built into a working smoke alarm, the disguised detector will alert you to the presence of radio transmitters carried into or placed in your home of office. When the unit detects a radio (RF) signal above the normal level for your location, it will silently alert you by means of a red LED that flashes about two times per second.

The SD300RF monitors a frequency range of 25 MHz to 2500 MHz. It measures 4" dia. x 1" deep and comes complete with mounting bracket, 9 volt alkaline battery and illustrated instructions.