REI Multilevel Protection Sunblock was developed specifically to stay on all day to protect you from the suns harmful rays. Features state-of-the-art polymers that allow the lotion to attach to the skin and therefore resist water and physically rubbing off. Bonds to the top layer of your skin works best when applied to cool, dry skin 20 - 30 minutes before sun exposure. Hypoallergenic, waterproof, sweat-resistant, PABA-free, greaseless and fragrance-free formula provides UVA and UVB protection. Feels silky smooth going on your skin plus, it breathes well and is comfortable to wear all day. Proper application gives lasting water- and sweat-resistance in most conditions all sunblocks should be reapplied to intense abrasion areas.