Sunscreen and Sunblock
What is UBA, UVB?
Ultraviolet according to its wavelength and bioeffect is made up of long wave UVA, mid-length wave UVB, and short wave UVC. While skin rash and skin burn are generally caused by UVB, SPF is the protector and filter to UVB.
What is SPF?
UVB cause sunburn, inflammation, swelling, peeling to skin. In simple words, SPF is the ratio of the time your skin starts to get sunburn after to before applying sunscreen. If your skin burn in 20 minutes in the sun without any sunscreen, and in 2 hours in the sun with sunscreen, then the SPF of the sunscreen is 6 (120/20=6).
What does * sign mean?
UVA is the main factor causing skin to turn dark and age. “*” indicates the level of blocking UVA.