The FM-105 Super High Frequency Occupancy
Sensor is a line voltage sensor that turns lighting
on and off based on occupancy, and can hold
lights off when sufficient daylight is available. It
detects motion via super high frequency (SHF)
electromagnetic waves and the Doppler principle.
Because it can detect motion through many dense
materials other than metal, the FM-105 can be
installed behind fixture lenses and hidden from view.