High-quality Si mirrors from Yongli's Strategic Cooperator the II-VI Infrared, with Diameters of 20mm. 25mm and 30mm are available.
The 30mm ones are widely equipped onto combo laser machines for high power laser sources, such as Yongli 300W CO2Laser Tubes, DLT-40Z
Fingerprints and processing residues are the most common reason to damage the CO2 Laser Mirrors/Reflectors. Periodically check the mirrors on your machine is necessary, and use swab and alcohal to clean the comtaminated mirror surface.