Manufacturing Tolerances Standard Metal Optics Attribute Unit Commercial Quality Precision Quality Manufacturing Limits Diameter Ø mm ±0.1 ±0.05 ±0.005 Thickness th mm ±0.1 ±0.05 ±0.002 Recommended Ø/th 10 6 4 Radius Tolerance % ±2 ±0.5 ±0.05 Rectangularity A/B arc min ±5 ±1 ±0.1 Surface Figure 3/3(3) 3/3(0.5) 3/1(0.2) Scratch - Dig 80-50 60-40 20-10 Surface Roughness (rms) nm 10 4 1 Copper Grade purity in % 99.90 99.995 single crystal Other Possible Materials Brass / Aluminum / Plastic