Bought the a 4 camera, 4k pro set from Aosu for my 2nd home/Airbnb. Very easy to install, the app and user interface are also very easy to use and adjust settings. The A.I. tracking is just what I needed and is very convenient. I liked the product and my 1st experience with Aosu so much that I bought a 2nd set for my main home. Very positive experience so far.