CR-39 Lens (1.499 Round-Top Bifocal Lens ) Resin Lens Detailed Product DescriptionSpecification :1). Round-top 2).Diameter :28/70 mm & 28/65mm3).Finished Lens Power : SPH(±0.00~±3.00)ADD(+1.00-3.00)4).Semi-Finished Lens Base:2.00,4.00,6.00 ,8.00 ,ADD (+1.00~3.00) 5) Rx-lens also available