optical lens imported material from Great Lake, never yellow! cr-39, 1.499 60mm diameter lens, UC/HC/HMC professional quality cr-39 1.499 optical lens, single vision resin lens, optical lens, cr39 lens: 1. high quality, never yellow! FDA, CE and Drop-ball test.2. excellent imported material from Great Lake. 3. Index 1.499, Diameter: 60mm; HMC, super thin and super white