Features: 1) ND: 1.499 2) Diameter: 70mm / 65mm 3) Curvature: 50B, 200B, 400B, 600B, 700B, 800B, 900B, 1000B 4) Concave base Features:1) ND: 1.4992) Diameter: 70mm / 65mm3) Curvature: 50B, 200B, 400B, 600B, 700B, 800B, 900B, 1000B4) Concave base: 500B5) Central thickness: 11mm - 13mm 1.499 Semi Finihsed S.V Lens (CR-39)