Specification of our plano-convex spherical lenses as follow: *Material:Bk7 or other materials *Focal length:+/-1% *Length tolerance:+0.0 ~ -0.1mm *Width tolerance:+0.0 ~ -0.1mm *Center thickness tolerance:+/-0.1mm *Surface Figure:lambda/2 at 633nm on plano side *Surface quality:60-40 stratch/dig *Clear Apenture>90% *Chamfer:0.25mm at 45 degree typical *Coating:optional