Coated with FGMC Blue Film
It can be used on DIY Astronomic Telescope Objective, DIY guidscope
Combined image quality: 1/4-1/8
Diameter tolerance: +0/-0.12 mm
Center thickness tolerance: ±0.2mm
Focal length tolerance: ±0.1%
Finish: 60/40
Eccentricity: 1'
Package includes: 1pc Achromatic Doublet Convex Lens.