quadlock magnetick puck, to stick your phone on magnetic surfaces. This model uses 4 neodymium magnets, wich are 12mm in diamater and 5mm tall. These are strong enough to hold you phone securely, but use it with caution.

I use it about a year and my phone working fine (iphone 13)

Hint: it s easier to assemlbly the 4 magnets first, and put them all in once, not one by one