... smooth,highly polished surface covered a thin coating.Mirror is usually a thin coating of metal ... Cost. Flat mirror,concave mirror,convex mirror,hot mirror,cold mirror,laser mirror,dielectric mirror,metal coated HR mirror,hyperbolical mirror etc.. Specifications of our mirror as follow ... thickness tolerance:+/-0.1mm *Surface quality:60-40 to 20/10 Scratch/Dig *Surface flatness:lambda/10 at 632 ...