Radio built-in sensor, detector that can be integrated into the window frame (Euro standard) with built-in reed switch that reacts when the included magnet is removed. Immediate or delayed alarm can be set. Frequency: 868 MHz. Power supply: 2x 3V lithium battery (CR2354, included). Dimensions (detector): 25 x 192 x 9mm, (magnet): D 9.5 x 3.2mm.