AmScope PA100X-IRIS Finite Plan Achromatic Darkfield Objective Lense with 100X Magnification and 160mm Tube

This is a 100X dark-field objective lens for biological DIN-standard microscopes. Standard bright-field objective lenses present low contrast due to their high numerical apertures. This lens' built-in iris provides control over the aperture, varying between 0.31 and 1.25. This allows for the intensity of the dark-field contrast to be easily adjusted.