Comprises a wooden board with painted white, mounted on non-skid plastic feet, and a removable turntable about 170mm in diameter.
The turntable has two orthogonal lines along its diameter dividing it into four equal quadrants.
Just beyond the rim of turntable, a circular scale graduated 90º-0-90º-0-90º × 1º is printed.
Also includes a Ray Box with a 12V, 24W bulb.
Supplied complete with a cylindrical convex lens of focal length about 75mm and two double slits, giving one wide beam slit and one each of single, triple and five slits.

Used with RAY TRACK APPARATUS OPTICAL SET (AR1110800-2), as shown in photo above.