... :55mm,60mm,65mm,70mm 2.material:CR39 lens 3.round top,flat top are available Bifocal lensSemi-Finished lensTechnical data:1.Material:CR ... /70mm,50base-1000baseSpecifications of 1.499S/F round top,S/F blended,S/Flat top28/70mm,200base-800basespecifications of semi-finished progressive ...