Material: Bk7, Fused Silica, Silicon, Sapphire, Germanium, CaF2, MgF2

Specifications
| Material |
Bk7, (other material upon request) |
| Focal Length Tolerance |
2% |
| Fringes |
1-5 |
| Irregularity of Fringes |
0.2-0.5 |
| Diameter Tolerance |
+0.0/-0.10 mm |
| Center Thickness(Tc) Tolerance |
+0.0/-0.10 mm |
| Centration |
3 arc minutes |
| Clear Aperture |
90% of Diameter |
| Surface Quality: |
60-40 scratch and dig |
| Coating |
Single-layer MgF2 AR Coateds |
Note: All material and size are available upon
request.