1. Pure copper silver chrome shell. 2. standard RMS thread 20.2mm. 3. Multilayer coated lenses. Product name: 195 flat field achromatic objective lens. Thread diameter: 20.2mm. Product multiple: 40X Parfocal Length: 45mm. Cconjugate distance: 195. Application: Used on biological microscope. Product advantage: The flat field achromatic objective is relatively clear than achromatic objective. Color: As Shown Material: copper Package Contents: 1X 195 Plan achromatic objective lens Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.