Feature:1. High Light Transmittance and Refractive Index: The lens is coated, has high light transmittance and high refractive index, making the image brighter and clearer2. Standard and Universal: The screw interface size is the international standard RMS size, which can be used by 95% of professional biological microscopes on the market3. High Quality Brass Material: Made of brass material with exquisite workmanship, this objective is corrosion resistant, can no worry about falling down4. Chrome Plated Shell: The shell of the objective is chrome plated, which is wear resistant, stable and durable, can use for long time5. Application: This microscope objective as the important fitting of microscopes in laboratory, mainly used for microscope magnification to observe objectsSpecification:Item Type: Achromatic Microscope ObjectiveMaterial: BrassModel: 4/0.10Use: Microscope AccessoriesInterface Size: Approx. 20.2mm/0.8in (International standard RMS size)Magnification: 4XNumerical Aperture: Approx. 0.10mmCover Glass Applicable Thickness: Approx.0.17mmMicroscope Applicable Mechanical Tube Length: Approx. 160mm/6.3inWorking Distance: Approx. 0.13mmCommon Rail Distance: Approx. 195mm/7.7inParfocal Distance: Approx. 45mm/1.8in.Package List:1 xAchromatic Microscope Objective1 x Storage Bottle