1Clearer Image: This lens is coated with high light transmittance, with high refractive index, and the image is brighter 2Automatic Rebound: Spring protection device, automatically rebound when touches the cover glass during observation to protect lens to avoid crushing specimen 3Brass Material: Made for brass material, fine workmanship, corrosion and fall prevention, exquisite and durable, chrome plated accuracy material for shell 4Wide Application: Screw interface size is the international standard RMS size, can be used by most professional biological microscopes on the market 5Basic Specifications: This lens has magnification of 100X, common rail distance of 195mm, and parfocal distance of 45mm