These are a brand new microscope Plan Achromatic objective lens set with high quality. It comes with 4X, 10X, 40X &100X plan Achromatic objective lenses. They fit common size (DIN standard) compound / biological microscopes. Features & Specifications: Plan Achromatic Objective 4X Magnification Power (4/0.1, 160/0.17) Plan Achromatic Objective 10X Magnification Power (10/0.25, 160/0.17) Plan Achromatic Objective 40X Magnification Power (40/0.65 (Spring), 160/0.17) Plan Achromatic Objective 100X Magnification Power (100/1.25 (Spring, Oil), 160/0.17)