... ,no need to take off the DPV from door! 1. New Peephole Viewer with Photo-snapping and doorbell functions 2. 3.5 ... viewer9. Automatic energy saving mode10. No need to change the door structure, 190 degree lens11.Accessories: Base Flange, Tightening Tool, ... and convenientOPTIONAL EXTENSION SPARE PARTS, SUITABLE FOR DOOR THICKNESS FROM 25~110MM!! 3.5" with door bell, video record, photo snapping,2.0M ...