Spectrometers of SL40-2 series are small-size two-channel spectrum analyzers. SL40-2 comprises two independent spectral channels of spectrograph, which are arranged in one housing, and an embedded linear detector. Each of the spectrographs is designed on the original optical schematic with aspheric mirrors and achromatic objective lenses. The spectrographs have a focal length of 40mm and aperture ratio 1/4.9. Diffraction gratings with different numbers of lines can be used in any of the two channels to allow adjustment both of the spectral range to be detected and the obtained spectral resolution.