3.5"/4.0" color video door phone, 4.0" CRT video door phone, 2-32buttons for multi apartments. 3.5"/4.0" color video door phone, 4.0" CRT video door phone, 2 ... methodsurface mountingSpecifications Working voltageAC110V-240VWorking currentB/W≤600mA, Color≤400mAMax. wiring distance80m/262feet(22AWG,4*0.5mm/ ... products,SKD/CKD, OEM/ODM available 3.5"/4.0" color video door phone entry system