Specifications D=Diameter ± 0.25 mm < 40 mm ± 0.50 mm 40 to 100 mm ± 1.0 mm > 100 mm F= Effective Focal Length ±7% CT=Central Thickness ±0.5mm ET=Edge Thickness ±0.5 mm Material : As per customer's requirement Centration : 3 arc min. Surface Quality : Mil-0-13830/80-50 Anti Reflection Coated |