Description These optical lens for physics teaching are made from premium glass materials, being safe and durable to withstand long time using. These concave lens and convex lens can help students learn and understand more specifically and obviously how to find the principle of light convergence. Compact size, easy to take, use and clean, you will feel the convenience of them. Features -Color:Transparent -Material:Glass -Size:6.00X3.00X1.00cm/2.36X1.18X0.39in - Made of premium glass material, these optical lens are with high durability to withstand long time using. - Well polished, smooth surface, and does not hurt hands when used, you can use with much more confidence. - Light weight and compact size, the optical lens is easy to carry and store, you will feel the huge convenience of them. - These clear optical lens can help students learn and understand more specifically and obviously how to find the principle of light convergence. - Practical teaching tools whether for students to learn about the properties of light or for teachers to conduct teaching.Package list: 7 x optical lens