Passive Infra Red (PIR) Motion Sensor, that detects human presence & turns the Lights On / Off.
It has inbuilt TIMER & Brightness (LUX) Sensor as well.
You can customise the timing for which it must remain on, after your are gone.
You can set the LUX level so that the Load does not turn on when there is enough day-light available !
Best suited for wash-rooms & cabines.