I have dipped this bad boy, with iPad inside, into the water several times, completely submerged. No problem but I try not to make it a habit. It also catches enough air in their to allow it to float. Again, I'd advise testing this in a pool but not the lake. However, it will float, assuming you haven't vacuumed too much of the air out. I'm buying one of these for a Christmas present but will actually be looking elsewhere for a lower priced product.
Also, the sound carries through fairly well. Next step is a wireless bluetooth receiver so I can watch Netflix in the hottub without turning off the jets haha thank God for America.
My only "Con" is that the transparent material feels like it could be torn without too much force. But I've had this for 3 months so far and no problems. Just continue to treat your iPad like a baby and you'll be fine.
Lol you can put your iPhone or whatever other phone in it. I just now realized that.