Samsung SmartThings Motion Sensor Trigger lights to automatically turn on when you enter a room or turn off when there's no motion for a specified length of time. Receive an immediate alert if unexpected motion is detected while you're away or asleep. Save energy by turning off lights and electronics when people leave home or when no motion is detected. Trigger your smart thermostat, A/C unit or portable heater to automatically adjust based on temperature or when people come and go. Measurements: 2 inches wide, 2 inches tall and 0.8 inches thick Additional Requirements: Samsung SmartThings Hub