... engineering laboratory, environment laboratory, production line for optics Lens, production line for machine numerical control. Amigo has ... lens:Optical lens: 1.499 Cr39 lens, 1.56, 1.60,1.67 optical lens, Polycarbonate lens, photochromic lens, Mineral lens, sunglasses lens, Cr39 Polarized lens ... relationship 1.56 / 1.61 photochromic lens (Single vision . Round top. Flat top . Invisible. progressive )