Specifications:
Material: BK7 grade A optical glass
Diameter Tolerance: +0.0, -0.15mm
Thinkness Tolerance: +/-0.2mm
Clear Aperture: >85% of diameter
Parallelism: <1 arc minute(Standard), <10 arc seconds(Precision)
Surface Quality: 60-40 scratch and dig(Standard), 40-20 scratch and dig(Precision)
Flatness: lambda/4 per 25mm at 632.8nm(Standard), lambda/10 per 25mm at 632.8nm(Precision)
Wavefront Distortion: lambda/4 per 25mm at 632.8nm(Standard), lambda/10 per 25mm at 632.8nm(Precision)
Bevel.: 0.25mmx45deg