Product Description Features: 1) Power source: DC 9V, AC 220V, DC 9V and AC 220V 2) Working current: : Surveillant current<15?́, alarm current: <30mA 3) Alarm sound: >85dB 4) Ambient temperature: -10 ~ 50 centigrade 5) Low battery alert: 7 days 6) Can be used separately as well as in combination of up to 40 items Packing: Packing dimensions: 42 x 50 x 50cm (120pcs) N. W.: 10.5kg G. W.: 19kg