English: Microscope objective marking: The Zeiss article number "440930" identifies the product (Zeiss CP-Achromat 10x/0.25). "CP-Achromat" describes the type of objective with regard to the correction of optical aberrations. An achromat is an optical system consisting of at least two lenses that reduces chromatic aberration (color errors for light of different wavelengths). The "C" is used for achromatic lenses that produce good image contrast. The "P" stands for "plan" (flat) and indicates that the optical field curvature that occurs with simple lenses has been corrected, so that flat specimens are imaged sharply in the center and at the edges simultaneously. "10x" indicates that the optical magnification factor of the intermediate image is 10 (with a suitable tube lens). "0,25" (with a German decimal separator = comma) indicates the numerical aperture 0.25 (a measure of spatial resolution). The infinity symbol shows that the objective was designed for microscopes with an infinity beam path. The horizontal line (no value given) indicates that the thickness of the cover glass is not important for this lens.