Sky Lens: Visual Light Transmitted (VLT) 37%. Category 2. Best for medium-low light conditions, fashion tint; Optical health benefits: Protection from harmful HEV light (98%) & UV (100%) while delivering eye relaxation and accurate color perception; Premium scratch resistance & impact protection lens; 4 Base lens curvature; Crafted from hand-polished M49 Bio-Acetate produced by Mazzucchelli; Optical grade 5 barrel stainless steel hinge for strength; Teflon coated hinge screws for durability; Custom heat tempered wire temple inserts for fit and strength; 48mm H - 142mm W - 145mm L (Medium Sized Frame); Weight: 33g