A specific range of wavelengths or light, from a minimum to a maximum, often named after a central value. The value of 633 nanometers is visible light, while 900 nanometers represents infrared light. Spectral band B633 includes those wavelengths (plus or minus 5 percent) of the 633 nanometer peak. Spectral band B900 includes those wavelengths (plus or minus 10 percent) of the 900 nanometer peak. The spectral band or scanning device is generally listed in bar code specifications.