visitor calling, video intercom, unlock, monitor. Auto turn off. With warning function. AV output. CMOS camera. With LED lights. It can connect image recorder . four wire connection. Specification: B/W. 4inch flat CRT screen Power supply: AC110V-240V Effective resolution: ≥420 Lines Operation temperature: -15°C??0°C Dimension: Monitor: 225(L)*190(W)*62(H)mm Camera: 127(L)*95(W)*35(H)mm Including: One indoor unit, one outdoor unit. one user manual, one steel for wall mount, screws, 3meters cable, one AV cable, one power adapter. Packing detail: Carton dimension: 0.068CBM 6sets in one carton GW: 15.6kgs CE approval