Features: One magnetic sensor can match with at most 8 remote controllers freely One remote controller could control several magnetic sensors Excellent home use product tiny and fashion Volume: 110db Alarm and door bell function for your option Low energy and long working time Easy to install Remote control: 20m Specifications: magnetic sensor: Voltage: 3V AAA*2pcs Stand by volume:100A Working volume:30mA Frequency: 433MHz Alarm respond time: 200ms Stand by time: 8-12months Remote Controller: Voltage: 12V Stand by volume:1A Working volume:15mA Remote control distance: 20m Stand by time: 8-24 months Size: magnetic sensor: 85mm*42mm*17mm Remote controller: 60mm*30mm*11mm Magnetic stick: 85mm*10mm*14mm Package Includes: 1*magnetic sensor(battery is not included) 1*Magnetic stick 3* remote control