OMAX Dry Darkfield Condenser NA 0.7-0.9 for Biological Compound Microscopes
This is an add-on dry darkfield condenser. It's for 4x, 10x and 40x objectives to observe low contrast samples, e.g. live blood samples. You may simply exchange the bright field condenser with this darkfield condenser in seconds as long as the mount size is 37mm.