What is the definition of sun protection factor and second lets ask the question if you don’t use a sunscreen how can you protect you?
sun-protection factor
SPF
An indicator on a sunscreen product of the relative degree of protection it provides against sunburn, compared to using no sunscreen. A product with an SPF of 15, for example, allows a person to be exposed to the sun, on average, fifteen times longer than if no sunscreen were applied.