Brief: Video Door Phone with Power Source of 18V DC and 4-inch Screen Model Number:colored VDP TK-881C+TK-818C Product describe: Screen size: 4-inch Resolution: 380 TV lines Power source: 18V DC Power consumption: Standby: 0.5W Working: 10W Working temperature: -10 to 50 degrees Celsius Dimensions (W x H x D): 186 x 222 x 55mm Available camera: TK-818c