Crystal orientation: 

C, A, M optional 

Diameter: 

20: 300 mm 

Radius of curvature: 

R10 - R150 

Wall thickness: 

> 1mm 

Edge thickness difference: 

 0.02mm 

Total thickness variation: 

 0.05mm 

C axis deviation: 

 2

Centration: 

 2 arc minutes 

Surface Quality

Better than 60-40 

Power N: 

 5 fringes 

Irregularity 

 1 fringe