Water, as an essential "lubricant", is the major natural substance which must always be present in the skin to keep it young, flexible and well hydrated. The presence or absence of water affects not only the physical properties of the stratum corneum but also its desquamation. Infra Red (IR) and Ultra Violet (UV) rays, present in daylight or produced by tanning lamps and beds, are the most dangerous external agents and undoubtedly the primary cause of premature skin ageing (photoageing). As a matter of fact, UV rays result in a much faster rate of degradation, decay and dehydration of the skin structure and of elastic and collagen fibers needed for maintaining ideal moisture levels. This constant, gradual dehydration, which occurs mostly in areas exposed to the sun such as skin-face, enhances the formation of wrinkles. Thus, spots and freckles appear, and the skin dries out and loses its radiance. UV rays also oxidize sebum, an action favouring the formation of free radicals, known as a primary cause of skin ageing. Therefore, whereas biological ageing is an unavoidable process related to genetic factors, suitable skin care products can be used to prevent premature photoageing induced by sun rays. Considering what has been said above, and taking into account the fact that the sun is indispensible for human life, MAVI has created special skin care products with variable moisturizing and penetration indices, suitable both for dry and oily skin. These products allow to use, for instance, the moisturizing product most suitable for one's own skin type, also choosing the moisturizing index in relation to specific climatic conditions. Moreover, the skin can be protected from adverse UV and IR rays activity, thanks to a continuous neutralization of free radicals.