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