That means it will block both UVA aging rays and UVB burning ... If you're going to be out in the heavy duty sun, you can step it up to SPF 50. But anything higher than that doesn't give you ...

Level of protection against sunburn producing rays. Score based on the SPF range found in our tests. Approximate ranges for tested SPF: Greater than 40 (excellent), 30-39 (very good), 20-29 (good ...