Our filters using multilayer high temperature vacuum assisted by epidural ion evaporation and deposition of nano materials, film density, narrow bandwidth, high cut-off rate, high transmission rate. Filter for separating a band monochromatic light from composite light. Let only one band pass through the light. The narrower the light band or the more pure the color, the stronger the recognition ability of the instrument. The filter is used for 850nm infrared light source, infrared light excitation (emission), semiconductor laser, CCD sensor (CHIP) and so on. Sensors through the filter can be infrared, cut off visible light and eliminate stray lights, so that the received signal more accurate, saturated, not distorted. Narrow band pass filter: 365nm narrowband, 450nm narrowband, 470nm narrowband, 532nm narrowband, 556nm narrowband, 635nm narrowband, 650nm narrowband, 780nm narrowband, 808nm narrowband, 830nm narrowband, 850nm narrowband, 940nm narrowband, 950nm narrowband, 980nm narrowband, 1046nm narrowband filter etc.. Then subdivide that each band can be divided into a narrow band filter. Application Iris recognition, wireless transmission equipment, infrared electronic whiteboard, infrared camera, infrared touch screen, infrared medical instrument, infrared ink recognition, face recognition sensor system, handheld infrared laser rangefinder, laser rangefinder, optical instrument, medical equipment and testing instruments etc.. Product name: 850nm narrow bandpass filter Optical index Center wavelength: 850 +/- 5nm Half bandwidth: 40nm Peak transmittance: 90% Cut-off depth: 1% Color and material: Mirror glass Round Size: 5.5mm Thickness: 0.55mm (If you need different sizes or different frequency bands and more quantities,