It successfully passed the sink test, in fact, I forgot about it and left it submerged for an hour with the paper towel inside. It didn't get wet nor left any trace of moisture. It comfortably fits an iPhone Pro Max. Now, in terms of functionality, it works normally and the buttons are pressed normally. The Face ID works fine and didn't bother me. The neck strap is very useful. Oh, and it floats!! It doesn't sink. Honest choice for its price.