Products with a sun protection factor of 15 and lower provide a basic level of protection against solar radiation. SPF, short for Sun Protection Factor, indicates how much longer you can stay in the sun without your skin reddening, compared to being without protection. For example, a product with SPF 15 theoretically allows you to extend the safe time in the sun fifteenfold. This level of protection is suitable for individuals with darker skin phototypes who tan easily, or for short periods of sun exposure at low radiation intensity.