Features: 1) Power source: DC 9V, AC 220V, DC 9V and AC 220V 2) Working current:: surveillant current85dB 4) Ambient temperature: -10 ~ 50°C 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