Purito Comfy Water Sun Block SPF50+ PA+++
How to use:
Apply liberally 15-30 minutes prior to exposure to sun or UV lights.
- PA & SPF: WHAT DOES THESE LABELS ACTUALLY MEAN?
PA (Protection Grade of UVA) ranges from PA+ to PA++++, and it signifies of the level of protection from UVA rays. The PA rating was adapted from the PPD (Persistent Pigment Darkening) method.
This test uses UVA radiation to cause a persistent darkening or tanning of the skin. PPD(PFA) is tested on a variety of volunteers who are exposed to UVA light. All test subjects are examined how long it takes for their skin to tan by UVA. Then the researchers compare the results between protected and unprotected skin.
SPF stands for Sun Protection Factor. It is a measurement of how long the sunscreen will defend your skin from UVB. SPF is tested on 10 variety people and it compares how much longer it takes for UVB to cause redness on the skin.