You can do optical experiments by this set of Optical equipment and you can adjust different light with your kids.Feautres:You can use this to do optical experiments, to explore the refraction of light.To help children become interested in physics.Promote the relationship between parents and children.Smooth surface, fine workmanship, harmless, will not hurt hands.It& 39;s stored in a protected box. No damage to equipment.Specifications:Material: acrylicBattery: 2 * AAAWater channel: 48 * 30mm / 1.8 * 1.2inSpherical lens: 14 * 6mm / 1.9 * 0.2inConvex lens: 48 * 10mm / 1.8 * 0.4inConcave lens: 18 * 10mm / 0.7 * 0.4inGlass brick: 40 * 12mm / 1.6 * 0.5in48 * 20 * 10mm / 1.8 * 0.8 * 0.4inGlass plate: 48 * 30 * 2mm / 1.8 * 1.2 * 0.08inChess: 23mm / 0.9inBiconvex lens: 72 * 35mm / 2.8 * 1.4inPrism: 40 * 35mm / 1.6 * 1.4inLaser-beam generator: 100 * 60mm / 3.9 * 2.4inPackage size: 235 * 160 * 50mm / 9.3 * 6.3 * 2.0inPackage weight: 435g / 1.0lbPacking List:1 * Laser-Beam Generator2 * Glass Brick3 * Mirror1 * Biconvex Lens1 * Water Channel1 * Prism2 * Chess1 * Spherical Lens1 * Convex Lens1 * Concave Lens2 * Battery Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store