Specifications:

Material ..................................                   ...B270¡¢ BK7 grade A optical glass

Diameter..................................... .........             max 200mm

Diameter Tolerance  ....................................       +0.0, -0.1mm

Thickness Tolerance ...........................................          ¡À 0.2mm

Clear Aperture ........................................................  >80%

 Parallelism ...................................................      <3 arc minutes

 Surface Quality ................................              20-10 S/D

Wavefront Distortion ............... .                                       l/4 per 25mm at 632.8nm

Protective Bevel                              or 0.2*45deg