Model: AJ140IPLD 40X magnification power Objective lens : Infinity-corrected PLAN field achromatic 40X/0.6, ∞/0, spring Objective working distance: 2.8mm 20mm mount thread (in diameter) Spring loaded for protecting lenses and slides Net weight: 4.2 oz (124 g) This is a brand new 40X/0.60 (spring) infinity PLAN field microscope objective lens to meet the special need during the examination. The working distance of 40X (2.8mm) objectives makes it possible to inspect the rough surface. It fits common size compound & biological microscopes. We also have infinity PLAN 100X objective lens availble. Specifications: Model: AJ140IPLD 40X magnification power Objective lens : Infinity-corrected PLAN field achromatic 40X/0.6, ∞/0, spring Objective working distance: 2.8mm 20mm mount thread (in diameter) Spring loaded for protecting lens and slides Net weight: 4.2 oz (124 g) Packing List: PLAN 40X/0.60 infinity-corrected objective with screw-on case