This is an excellent and economical set for introductory ray optics. The laser ray box projects one, three or five parallel bright beams and is equipped with a momentary switch for safety. A vinyl template with a degree circle and a linear scale forms the optical disk; the set includes seven clear acrylic optical elements and a mirror with adjustable curvature for investigating refraction, lenses, prisms and mirrors. The bottoms of the acrylic elements are frosted to show the ray paths inside them. The set also includes a manual and storage box. Please note: This product emits laser light. Max. output power<1mW per beam. Wavelength 650nm. Class IIIa laser product. Contents: Wall-mount Power Supply, Laser Ray Box (1, 3 or 5 rays), Parallel-sided Block, Trapezoidal Prism, Right Angle Prism, Biconcave Lens, Biconvex Lens, Semicircular Lens (solid), Semicircular Cell, Flexible Template-ruler & protractor, Adjustable Mirror-plane/concave/convex, Aluminum Storage Case and Activity Guide.