Narrow band interference filter is a narrow band interference filter bandpass filter, which uses a dielectric multilayer film and the interference of the metal, from the incident light, select a specific wavelength of a half-peak bandwidth (half the peak value) is 1nm to 40nm. Narrow-band interference filters can be replaced as expensive as grating spectroscopic devices are widely used in optical experiments and industrial fields. Product parameters: Material: Optical grade glass Size Tolerance: +0.0 /-0.2mm finish :60-40 Clear Aperture:> 90% Flatness: / 4 at 632.8nm Parallelism: <1 arc min