Power Source Transformer or adaptor ( AC 110V-240V ) Assurance_temperature -40~+ 50oC Camera 1/3 CCD (color) Lens F=2 ; Viewing angle=92.8° Min Illumination 0.1 Lux; Resolution>450 lines Monitor CM-06DNRL(color); Max_Wiring Distance RVV4x0.5 multi-core wire for transmission distance within50m, RVV2x0.5 multi-core wire and 75-5 video wire for up to 200m Dimension 230x230x69mm(color box for 1 set) Weight about 1.35kgs/set Tv System PAL or NTSC Ring Bell 3 kinds of ring tones available Wiring 4 wires in polarity. Call Function Dual Conversation is available. Call between monitors is available Extension One door station supports four indoor phones,including one main monitor and three extra monitors Door Release function Signal Unlocking LED You can enjoy a constantly clear & bright picture on the screen at any light level from 0.1 Lux (at night or dark Place)