Lens material: ABS. Preferred material, good quality, safe, durable and functional. Batteries required: 2 AAA batteries (not included) Three-way linear : The direction of the light can be adjusted with a screwdriver. Optical experiments: refraction of light, convex lens refraction, lens refraction, prism refraction, plane mirror reflection, diffuse reflection, convex mirror reflection, concave mirror reflection, etc. Physical Optics Experiment Set: Will give your child a understanding of physical optics, making learning easier and more enjoyable! Name: Optical Experiment Kit Colour: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 Three-Way Linear 1x Multifunctional Reflector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.