The Philio 4 in 1 Sensor combines a PIR (Motion) sensor, door/window sensor, light sensor and a temperature sensor, all in one small package. The detector includes four sensors. PIR (Motion) Monitors changes in infrared level and movement that indicate a persons presence. Door/Window Sensor Detects the opening or closing of a window, door, gate or roller blind and sends an alert to the Z-Wave network. Light Level sensor Measures a room’s light level (LUX) and reports this to the Z-Wave network Temperature sensor Control and measure any room’s temperature. The sensor’s Lithium battery should give you more than 2 years of use in normal situations, the sensor sends an alert to the network when the battery needs replacing.