a scale for rating the level of sunburn protection in sunscreen products. the higher the sun protection factor, the more sunburn protection it gives. sunscreens with a value of 2 through 11 give minimal protection against sunburns. sunscreens with a value of 12 through 29 give moderate protection. sun protection factors of 30 or higher give high protection against sunburn. also called spf.
出典:Wiktionary