CR39 Round Top / Flat Top / Blended Top (Invisible) Bifocal Lenses Finished lenses: a) Nd: 1.499 b) Power range: Sph: 0.00 ~ -2.00 / Add: +1.00 ~ +3.00 Sph: 0.00 ~ +3.00/ Add: +1.00 ~ +3.00 c) Diameter: 70/28mm, 70/24mm, 65/28mm Semi-finished lenses: a) Diameter: 70/28mm, 70/24mm, 65/28mm b) Base: 200, 400, 600, 800 c) Add: +100 ~ +300 Envelope/box/carton
