Specification of our narror band filter as follow:
Material:Filter Glass,BK7
Dimension: 4mm-160mm - 0.20mm
Squares/Rectangles:1mm-165mm
Thickness:0.5mm-4mm
Thickness tolerance:+/-0.01mm-0.1mm
Paralism: Up to 3 Arc minutes
Edges:Fine
Ground Flatness:Up to Lambda/10
Surface quantity: 80/50-20/10 Scratch/Dig