This compact Direct Vision Spectroscope is a very useful device for measuring the wavelength of light.  An adjustable slit allows the light to enter the black chamber and the viewing eyepiece carries a 600 line/mm grating.  The eye sees the incoming light split into its colours or wavelengths that appear to be deflected to the right hand side.  The coloured bands appear over a scale calibrated in nanometres (nm) with each digit on the scale representing 100nm. 

Size: 190 x 100 x 25m.  Instructions included.  Made in Australia.