sun protection factor: the effectiveness of a sunscreen in protecting the skin from the sun's ultraviolet UVB radiation, as rated on a scale of increasing protectiveness, the number being the ratio of the radiation dose needed to produce minimal redness when using sunscreen compared to the dose needed to produce the same redness without sunscreen:An SPF of 15 will allow you to stay in the sun 15 times longer.
更多spf例句
SPF is in our moisturizers, lip balms, eye creams, and make-up.
You can buy a cellphone the way you choose SPF-labeled sunscreen: by SAR, or specific absorption rate.