Specifications: Material: ZnSe Laser Grade C.V.D. type Diameter Tolerances: +.000", -.005" Thickness: ±.010" Surface Figure: < 1/40 wavelength @ 10.6µ Centration: < .001" Focal Length Tolerance: ±1.0% Surface Quality: < 40/20 scratch-dig Laser Finish Spectral Performance: Standard AR Coating type Both Sides @ 10.6µm (AR) Absorption: < 0.25 % total Reflectance: < 0.20% per surface @ 10.6µm Transmittance: > 99.0% typical