Specifications Material: optical glass, fused silica Diameter: 0.5 – 5mm Dimension tolerance: ± 0.02mm Surface quality: 40/20 – 80/50 Scratch and dig Surface accuracy: Lambda/2 – 2 Lambda @ 632.8nm Centration: 3 arc minutes Protective Bevel: allowed up to 0.1mm AR Coating: Upon request