Feature:1. BRIGHTER AND CLEARER IMAGE: Lens after coating bring high transmittance, high refractive index, possess brighter and clearer image2. WITH PROTECTIVE DEVICE: Spring protection device can automatically rebound when the cover glass is encountered during observation, to protect the lens from crushing the specimen3. CORROSION RESISTANT BRASS: Brass material with fine workmanship, corrosion resistant and not easy to fall, exquisite and durable, the shell is chrome plated with accurate materials4. UNIVERSAL SCREW INTERFACE: The screw interface size is the international standard RMS size, which can be used by 95% of professional biological microscopes on the market5. 40X MAGNIFICATION: This is a 40X high magnification objective, helps a lot in study, work or research, useful, helpful and practicalSpecification:Item Type: Achromatic Microscope ObjectiveModel: 40/0.65Material: BrassUse: Microscope accessoriesInterface Size: Approx. 20.2mm / 0.8in (international standard RMS size)Numerical Hole Diameter: 0.65mmCover Glass Applicable Thickness: 0.17mmMicroscope Applicable Mechanical Tube Length: Approx. 160mm / 6.3inWorking Distance: Approx. 18mm / 0.71inCommon Rail Distance: Approx. 195mm / 7.68inParfocal Distance: Approx. 45mm / 1.77inSpring: Yes(automatic rebound).Package List:1 x Lens1 x Storage Box