For the examination of the spectral composition of light sources radiant bodies etc. The instrument gives a brilliant spectrum with a dispersion of approx. 11°. The slit is of fixed width and is protected by a glass cover plate. The eyepiece is mounted at the end of a draw tube and is adjustable in relation to the slit so that a sharply defined spectrum can be obtained. Both sodium D lines are independently resolved (589nm and 589.6nm) and the Fraunhofer lines are visible.Length: 80mm.Diameter: 19mm.Supplied in a carrying case.