Which brand do you suggest for sunglasses?

[round eyeglasses frames]

I am planning to buy a pair of sunglasses, but I don't quite know about this kind eye wear, only know they can be used to UV protection, I just want to know do all sunglasses have the effect? I know what are UV rays, but how can I tell if the sunglasses provide 100 percent of UV protection, and which brand do you suggest for buying sunglasses?