Bausch and Lomb antique brass 97X oil immersion microscope objective. It has an n.a. of 1.30 and the magnification is sometimes listed as 1.9 and other times as 97X. I have four each but the sale is for one each. They have been visually checked and no signs of oil incursion into interior elements can be seen. Every objective is free from dust, fungus, scratches and element separations.storage containers. They are in nice cosmetic condition with the brass showing signs of wear consistent with age. Thank You for Looking!