cylindrical mirrors Material: flint glass, UV fused silica, infrared fuses silica,CaF2, Ge, ZnSe, Si, etc. Diameter: 4mm-- 200mm Focal length: 4mm-- 200mm Thickness tolerance: ¡À0.1mm Surface accuracy: > ¦Ë/4 Surface quality: 40/20 Clear Aperture: 90% Reflecting Coating: Au film, Ag film, Al film, dielectric film, metal film, Co2 laser reflecting film, etc.