I have installed the doorbell (mechanical doorbell required) at my door. Installation was easy and they supplied all required hardware including a wedge for those situations not parallel to the door.The doorbell works in that it rings my mechanical bell, and plays a doorbell chime on it’s speaker. The video quality is great (although you may need to install the unit high enough to see their face).The problem is with the suggested IOS App. I can see and hear the visitor, but am unable to respond to them. The person at the door cannot hear me. After a week or so working with support, they admit it is the IOS app.Note: I tried this on all my family devices iPhone11 Pro, iPhone 11Max, iPad mini 2, iPad mini 4. All had the same problem.It is great that they have USA support line till you find it is just someone to relay your issue. They only open a ticket and send an email to China. Technical support is off-shore. A generic solutions email was sent 24 hours later. After a few days of swapping emails, they agreed they are working on a solution to their app.Summary: This is a great video doorbell unless you want to communicate to the visitor at your door but they are working on it.UPDATE: I have multiple devices using SmartLife application (Tuya devices). The interface is just close enough that I decided to try that application. Surprise: In the SmartLife IOS app, I was able to install the doorbell and it works completely. Two way communication does work on that app and because I have other devices using smartlife app, I have one less application on my phone.This is a great doorbell for the price, especially if you already have a mechanical doorbell.The wired installation makes this more reliable and secure as I do not need batteries and stealing it will need tools. Also, part of the doorbell installs indoors, so stealing the doorbell might leave it non-functional.