To be honest, for the price I bought it (around 18 euros), I didn't expect something great, but I was really surprised with what I received. The 1 star is given because I can't give it 0. Build quality: The lowest possible.
Screen-camera resolution: Equivalent to a 20-year-old mobile phone (it reminded me of my youth).
Menu: Non-existent.
Functions-settings: Minimal.
As for the application, I don't know since I didn't use it. I consider it to be a completely overpriced smartwatch (God forbid), which is not worth it, as it doesn't even come close to its value. However, the most important thing is that you can't adjust the time and date. There is no relevant setting in the menu and I assume, since I didn't try it, that in order to set the time, you need to insert a SIM card to receive data from a GSM network, something that is not mentioned in the product description. So if you plan on using it without a SIM card, just don't get it, unless you don't mind seeing the time of Uruguay or Australia (whatever suits you) or waiting to open it at 10:00 on 01/01 (that was the time mine was set to). After all this, and because my child wanted to see the time of Greece and not Shanghai or Greenwich, it was packed again with all its accessories and a return request was made.