Specifications: Material:---------------------------------------------N-BK7, Fused Silica, N-SF10, Silicon, Ge,CaF2, etc. Diameter Tolerance:---------------------------+0.0/-0.15mm Focal Length Tolerance (mm):--------------+/-2% Centration:----------------------------------------<3 arc minutes Clear Aperture:---------------------------------->85% Surface Figure (per 25mm@632.8nm)----<1.5λ IRR ( @632.8nm)--------------------------------<λ/4 Surface Quality:-----------------------------------60/40 Protected Bevel:----------------------------------<0.25mmx45deg Coating:--------------------------------------------uncoated, AR, HR, PR Coating, etc.