Support: Wireless alarm systems DAHUA ; Sound pressure level: 110 dB ; Frequency bandwidth of the system: 868 MHz ; Radio communication range (at open area): max. 1600 m ; Color: Blue ; Power supply: 4 x Battery 3 V CR123A (included), 12 V DC ; Maximal current consumption: 420 mA ; Backup time: 3.4 years ; Operation temp: -25 °C ... 60 °C ;