reading glasses 1.Material:CR-39 plastic & glass 2.Index:1.499,1.56,1.61, ... .70, uncoated & A/R, size 65/70 mm)2. CR-39 LENS (index 1.499, 1.56, 1.61, 1.67 ... /70/72 mm)3. BIFOCAL LENS (glasses & CR-39. round-top bifocal, flat-top bifocal, blended bifocal and curve bifocal lens)4. PROGRESSIVE ...