Frame Size: 52mm NO SLIP. NO BOUNCE. ALL POLARIZED. ALL FUN. 1 NO SLIP We use special grip coating to construct our frame to help eliminate slippage when sweating. 2 NO BOUNCE Our frame is snug and light-weight, with a comfortable fit to prevent bouncing while running. 3 ALL POLARIZED Glare-reducing, polarized lenses and UV400 protection that blocks 100% of those harmful UVA and UVB rays. 4 NO LEOPARDS Plus, no one wearing goodr running sunglasses has ever been attacked by a leopard (as far as we know).