Proderm. Intra-dermal technology. SPF 30+ protection for 8 hours.. Non-greasy. Very water resistant. astaZanthin. Parsol 1789. Unique Technology: UVA and UVB radiation penetrate and damage unprotected skin. Most sunscreens stay on the surface of the skin and act as a barrier. Their effectiveness can be significantly reduces by swimming and towel drying. Sea & Ski All Day 30 is rapidly absorbed into the skin and has been clinically proven to provide 8 hours protection from UVA & UVB radiation. Studies on Sea & Ski All Day 30 confirm, when applied correctly, All Day 30 maintains a SPF level of at least 30 after 8 hours. Sea & Ski encourages fair skinned people in particular to take extra care in the sun, reapply and stay protected. Ordinary sunscreens only cover the top on the epidermis, which UVA and UVB rays goes past; Sea & Ski All Day 30 reaches the dermis, which is under the epidermis to provide protection.