Item Type: Achromatic Microscope Objective_x000D_Model: 40/0.65_x000D_Material: Brass_x000D_Use: Microscope accessories_x000D_Interface Size: Approx. 20.2mm / 0.8in (international standard RMS size)_x000D_Numerical Hole Diameter: 0.65mm_x000D_Cover Glass Applicable Thickness: 0.17mm_x000D_Microscope Applicable Mechanical Tube Length: Approx. 160mm / 6.3in_x000D_Working Distance: Approx. 18mm / 0.71in_x000D_Common Rail Distance: Approx. 195mm / 7.68in_x000D_Parfocal Distance: Approx. 45mm / 1.77in_x000D_Spring: Yes(automatic rebound) 1BRIGHTER AND CLEARER IMAGE: Lens after coating bring high transmittance, high refractive index, possess brighter and clearer image 2WITH PROTECTIVE DEVICE: Spring protection device can automatically rebound when the cover glass is encountered during observation, to protect the lens from crushing the specimen 3CORROSION RESISTANT BRASS: Brass material with fine workmanship, corrosion resistant and not easy to fall, exquisite and durable, the shell is chrome plated with accurate materials 4UNIVERSAL SCREW INTERFACE: The screw interface size is the international standard RMS size, which can be used by 95% of professional biological microscopes on the market 540X MAGNIFICATION: This is a 40X high magnification objective, helps a lot in study, work or research, useful, helpful and practical 1 x Lens 1 x Storage Box