... and Round Top Bifocal, CR39 1.56 Progressive Short CR39 1.56/1.499 Single Vision,1.70 aspheric lens, 1.70 Titan lens, CR39 ... - +4.00 / -2.25 - -4.001,Index: 1.499 1.56 1.61 1.70Specific gravity: 1.16Abbe value: 44Dia: 55mm 60mm 70mm 75mmTransmission: above ... City, Jiangsu Prov. ChinaTel: +86-511-88015557,Mobile 18362038898 CR39 1.49 & 1.56 Optical Lens,Eyewear,RX lenses