1.499 optical lens imported material from Great Lake, never yellow! 55mm diameter, HMC professional quality, CE,FDA, ISO 1.499 optical lens, 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: 55mm; HMC, super thin