... " CRT video door phone, 2-32buttons for multi apartments. 3.5"/4.0" color video door phone, 4.0" CRT ... of the CX and NCX outdoor unitHousingABS materialScreen4"flat CRT, 3.5" or 4" TFT LCDAdjustmentsvolume,brightness,contrast,saturationInstallation methodsurface mountingSpecifications ... certificatesBusiness modeFinal products,SKD/CKD, OEM/ODM available 3.5"/4.0" color video door phone entry system