The right UVA and UVB protection

I believe SPF stands for Sun Protection Factor. Basically if it's SPF of 15 you can stay out 15 times longer then you can without any protection without burning. So if you can stay out for an hour without burning without protection with it you could stay out for 15 hours. I was told by doctors and others that anything over SPF of 8 was a waste. It doesn't really change anything because by then it needs to be reapplied anyways due to fade time. So you are better off with one that is more realistic in time span.