Sun Protection Factor Of 30 Technically provides You With 30 Times You Natural Protection Use If You Usually Show Response To Sun Exposure In 30 Minutes SPF 30 Will Allow You 7 And 1/2 Hours, Under Normal Skin Conditions, Before Seeing A Response To Sun Exposure 30 X 15 = 450 Minutes 30 Minutes Worth Of Sun Exposure Damage Will Therefore Be Limited To 1/30 Of Total Damage That Would Normally Occur To Unprotected Skin