Absorption glass ND Filters
| Material | Optical Neutral Density Glass |
| Dimension Tolerance | +0.00/-0.10mm |
| Thickness Tolerance | ±0.20mm |
| Clear Aperture | >90% |
| Parallelism | 3' |
| Surface Quality | 60-40 |
| Flatness | 2λper 25 mm |
| Optical Density Tolerance | ±5% |
