There's nothing quite like walking on the beach on a beautiful day. But you don't want to head there without a good sunscreen. Consumer Reports tested 22 sprays, creams, and lotions, including ones from Banana Boat and Coppertone.  GInger skinner, Product protected against UVB radiation. That's what causes sunburn and what the SPF number refers to."     Another potential danger from the sun - UVA radiation, which can cause cancer and also ages skin, penetrating even deeper than UVB rays.     "The testers also evaluated how well the sunscreens block UVA radiation. There's still no standardized labeling system, so most just say they've got UVA protection."   To test, sunscreens are applied to people's backs at an outside lab. Then they're subjected to either  UVA rays or UVB rays.         And since swimming in the water can wear off sunscreen, Consumer Reports tests for water resistance as well.    : Ginger Skinner "We did find a number of sunscreens that provided excellent protection against UVB rays and very good protection against UVA radiation."     Two at a good price - Up & Up Sport - a spray from Target with SPF 30, and Equate Baby lotion from Walmart, with an SPF of 50.       And when you're at the beach, remember to reapply sunscreen right after swimming or about every two hours.