I heard the FDA was going to make sun block companies say on the label that anything over 30 is useless???? Just a rumor perhaps?

But I use 30 and I don't put a whole lot on and it seems to work fine even at the beach. The thinnest coat spread evenly over seems to work. If I lived in So Cal I think I would bring some with me on long rides because my Irish skin burns like the devil. The stuff is definitely not as water proof as they would like you to believe. You should put it on 1/2 hour before going out in the sun.