+**Spf** (Sun Protection Factor) quantifies a [sunscreen](/wiki/Sunscreen)'s defense against the sun's damaging [UV radiation](/wiki/UV_Radiation). It extends the time skin can safely endure sunlight without burning.
+## See also
+- [Sunburn](/wiki/Sunburn)
+- [Melanin](/wiki/Melanin)
+- [Skin Health](/wiki/Skin_Health)
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