I used this for swimming and snorkeling for hours on hot tropical vacations.  Kept my head from getting burned, very comfortable to wear, small and compact for travel.  i wore this and a rash guard on speed boats, and also all day at a Waterpark going down slides, tubes, and such and under water with NO Problems.  my head never got burnt or red.  I don't care how funny i look, i now wear head protection, a long sleeve rash guard, and cake on sunscreen every 80 minutes. Ive had sun poisoning before and burnt bad and never want that again.