Marlo is an all day water resistant sunscreen barrier protecting against the harsh conditions faced by surfers. To maximize its effectiveness and your surf time we recommend rubbing the zinc into your skin in a circular motion as you would a normal lotion – then finishing with a second visible layer. Note the layer of Marlo does not need to be thick – just rubbed in and spread evenly to the areas you want to protect. Zinc is a physical barrier so if you can see it you will be covered.