Round window Window are of high precision dimension control, minimal transmitted beam deviation, high surface quality. With those excellent features, the bk7 , sapphire, infrared etc window is widely use in projection optics systems, imaging and optical measurement system. Our optical round windows include caf2 round window, mgf2 round window, znse round window, zns round window. Capacity: Material: optical glass, fused silica, silicon, germanium, caf2, mgf2, sapphire, znse, zns Diameter: 1 to 500 mm Diameter tolerance: +0/-0.02 mm Thickness tolerance: 0.01 mm Surface quality: 10-5 Surface figure: /10 Parallelism: 1 minute Coating: uncoated, ar, hr, beamsplitter ect.