plano-convex,double-convex,plano-concave,double-concave Material:BK7,Fused Silica,ZnSe,ZnS,Si,Ge,etc.,Specification ... -10 scratch and digBevel:0.25 mm x 45°Paraxial Focal Length:±2% Specifications:Material: BK7 grade A optical glass, or other ... optical materialDimension Tolerance: +0.0, 0.1mmCenter Thickness: ±0.2mmFocal Length Tolerance: ±1%Surface Quality: 60-40Surface Figure: λ/2@ 633nm on ...