Specifications Material:Calcium Fluoride Single Crystal; Transmission Range:0.17-7.8 um; Diameter Tolerance:+0.0/-0.15mm; Thickness Tolerance:±0.2mm; Clear Aperture:>90% Diameter; Parallelism:< 3 minutes; Surface Quality:S/D=80/50; Flatness:λ/2 at 633nm per 25mm; AR Coatings:Optional |