Lens Material: ABS. Preferred material, good quality, safe, durable, and functional. Batteries Required: 2 AAA batteries (not included). Triangular Linear: The direction of light can be adjusted with a screwdriver. Optical Experiments: Light refraction, convex lens refraction, lens refraction, prism refraction, plane mirror reflection, diffuse reflection, convex mirror reflection, concave mirror reflection, etc. Physics Optics Experiment Set: Provides your child with an understanding of physics optics, making learning easier and more enjoyable. Name: Optical Experiment Set Color: White Material: ABS Size: 24 x 14 x 3cm Package Contents: 1x 3 Bi-convex Lens 1x Single Concave Lens 1x Acrylic Glass Brick 1x Single Convex Lens 1x Double Concave Lens 1x Triangular Prism 1x Triangular Linear 1x Multifunctional Reflector Only the above package contents are included; other products are not. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3 cm.