The OD-780W from Opto Diode Corp. is a purely spectral output double heterostructure LED in a TO-46 package with a flat window. The diodes emit at 780-nm peak with a typical 25-nm spectral bandwidth. Unlike standard double heterostructure LEDs, they contain no secondary peak emission, thus reducing the likelihood of false or incorrect results. These spectral characteristics suit them for fluorescence and spectral comparison applications where narrowly defined "color" is of prime importance. Custom wavelengths with peak output ranging from 700 to 860 nm are available.