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 We Also Offer Special Coatings To Meet Our Customers Needs. Please Call or Contact Us. Ultra Low Absorption AR Coating type Both Sides @ 10.6µm (ULA) Absorption: < 0.15 % total Reflectance: < 0.25% per surface Transmittance: > 99.0% typical Dual Band AR Coating type Both Sides @ 10.6µm and .633µm (DBAR) Absorption: < 0.30 % total Reflectance: < 0.25% per surface @ 10.6µm Transmittance: > 98.5% @ 10.6µm with > 90% @ .633µm