I got a couple of inflatable pfd's for father's day. they are cool not as hot as the regular pfd's, But, over the weekend i was got checked by the game warden and my pfd was off, and he told me that if you are not anchored you must have one on all the time, I did not know this. Now i was informed, also if you keep a regular one in the boat you can you can take off the inflatable one while in motion. He was real nice about it, i wanted to pass this on to you all. Yes it is in the book.