... 2.Diameter: 60m5,70mm,75mm 3.Well designed base curve Semi-finished lens(Optical lens)Index: 1.49, 1.56, ... /28mm, 70/24mm)Flat top: (70/28m, 70/30mm).Progressive semi-finished:Diameter 75mm, short corridor 14mm, Regular corridor 17mm.polarized ... ,which equipped with Germany grinding machines(Schneider/Loh),and leybold coating machines.Our prescription lenses:single vision,bifocal lens,progressive lens ...