<prompt> A sunscreen ointment has a Sun-Protection-Factor SPF of 15.How much of UV radiation it filters out.15859398  <response>: SPF 15 means that 115th of the burning radiation reaches the skin through the recommended thickness of sunscreen SPF 15 sunscreens filter out about 93 of UVB rays, while SPF 30 sunscreens filter out about 97, SPF 50 sunscreens about 98 Ref: 