The 10RG050-600-1 is a plane ruled reflection grating, with dimensions of 25 x 25 x 6 mm, 50 grooves per mm, 0.9° nominal Blaze angle, first order Littrow nominal wavelength of 600 nm, and coated with an aluminum coating. 
Designed for first order Littrow use, Richardson Gratings\' plane ruled reflection gratings are blazed for specific wavelengths and generally have high efficiency at those wavelengths. Ruled gratings comprise the majority of diffraction gratings used in spectroscopic instrumentation and are especially useful in systems requiring high resolution.