6.6" x 6.6" ND 2.1 Neutral Density Filter - 7 Stops - 0.78% Transmission. Lindsey Optics Brilliant FS IR ND filters are full-spectrum neutral density filters that attenuate all wavelengths of light including UV, Visible and Infra-Red. Cutting the Infra-Red energy eliminates "Infra-Red pollution" which can cause unwanted color shifts with digital cameras. Constructed from solid glass, the neutral grey color won't ever change. The grey color is in the glass itself, it is not in a plastic layer or a surface coating. These solid glass filters have a durable anti-reflection coating reduces reflections on both filter surfaces. This reduces stray light resulting in brilliant images with vibrant contrast and color saturation. Available in ND values ND 0.3 and ND 3.0, they offer light reduction between 1 stop, which is 50% transmission, and 10 stops, which is 0.1% transmission All Lindsey Optics filters have serial numbers for improved traceability by dealers and rental houses.