Protecting skin from harmful external factors is the key to keeping skin looking both healthy and beautiful. Extensive research confirms that one of the most destructive contributors to skin damage is the daily exposure to UV rays, which causes photo-aging, including wrinkles and dark spots, whilst compromising the condition of skin cells and the immune system. Other considerations are invisible oxidative pollutants in the air, and daily temperature and humidity changes in the environment. Shiseido's UV-care products are based on years of exclusive research and development in protecting skin from damaging agents and promoting skin's natural beauty. SPF (Sun Protection Factor) shows the level of protection from sunburn caused mostly by UVB rays. A higher number equals higher protection. PA shows protection against UVA rays, the rays causing photo-aging.