I bought these glasses to replace a pair of Maui Jim's I had. My MJ's were just too heavy with the glass lenses. I needed a pair of polarized sunglasses that I didn't have to worry about falling off my head every time I looked down. These glasses stay on. They have rubber grips on the nose and on the earpiece that keep them in place. Even sweating, they don't slide. I would say the lenses are medium in darkness. I like the brown lens color best. They aren't as dark as the black. Images through these lenses are very clear and the colors are crisp and bright. I haven't dropped them yet so I cant attest to their durability. I would purchase them again.