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, and 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.