To study color mixing and behavior of light with lenses and refraction blocks (not supplied), where parallel ray of lights are required. Has a built-in lens to produce parallel rays of light. Strong Plastic Construction, with finned sides for heat dissipation. Comes complete with 3 filters red, blue and green, 3 slit plates with one, two, three and four slits. Operates on 12V 2Amps dc. Size 6 1/2"(165mm) x 3"(75mm) x 2 1/8"(55mm).