The PP-IRFS-12.7-2.0-DM85-AR131 from OPTOMAN is a Wavelength Separator Optical Filter that has a diameter of 12.7 mm and thickness of 2 mm. It has a clear aperture above 90% and surface quality of 10-5 S-D (scratch-dig) on both sides (S1/S2). This mid IR-grade fused silica (IRFS) optical filter has a surface flatness of up to lambda/2 (at 633 nm) and parallelism of up to 30 arcsec. It has a protective chamber of 0.2 - 0.3 x 45 deg and an angle of incidence of 17 deg. This optical filter has an ion beam sputtering coating reflective surface with high reflectance above 99% (for p-polarized light) & high transmittance of over 97% (for s-polarized light) and an anti-reflective surface with a reflectance of less than 0.75% (for p-polarized light).