This wireless peephole door phone system is widely used in apartment, hotel, villas, office, building, etc.It is made of peephole (outdoor camera unit), indoor monitor and wireless unlock control.Peephole can install in variable types of doors (the door thickness ranges from 35 to 110mm, the peephole diameter of door ranges from 14 to 38mm); the indoor monitor can be handheld or placed on the table or hang on the wall.
Other Thoughts:While it's not on par with some of the very famous brand Peephole Viewer Video Doorphone, the item quality is more than adequate for my needs. Setup was straight-forward and the included instructions were easy enough to follow.
Other Thoughts:I needed a secondary Doorphone for my apartment. The original bell on the door was not loud enough to hear in the back bedrooms. This item fits the bill. The volume control on it's highest setting is loud enough to hear throughout the apartment.