60X Achromatic Objective Brass Lens for Biology Laboratory Microscope 20.2mm Interface Item Type: Achromatic Objective Model: 60/0.85 Material: Brass Use: Microscope Accessories Interface Size: Approx. 20.2mm / 0.80in (International Standard RMS Size) Magnification: 60X Numerical Aperture: Approx. 0.85mm / 0.03in Cover Glass Applicable Thickness: Approx. 0.17mm / 0.007in Microscope Applicable Mechanical Tube Length: Approx. 160mm / 6.30in Working Distance: Approx. 0.53mm / 0.02in Common Rail Distance: Approx. 195mm / 7.68in Parfocal Distance: Approx. 45mm / 1.77in Spring: Yes (Automatic Rebound) 1¡¢Clearer Image: This lens is coated with high light transmittance, high refractive index, and brighter image 2¡¢Automatic Rebound: Spring protection device, automatically rebound when touches cover glass during observation, protect lens from crushing specimen 3¡¢Brass Material: Adopts high quality material, fine workmanship, corrosion and fall prevention, exquisite and durable, chrome plated for shell 4¡¢Application: Interface size is the international standard RMS size, can be used by most professional biological microscopes on the market 5¡¢Basic Specifications: This lens has 60X magnification, common rail distance of 195mm, and parfocal distance of 45mm 1 x Achromatic Objective 1 x Storage Box