These are some physics optical lens applied to understand the principle more intuitively. Adopting good materials, they are safe and for long period to use. Small size, easy to use, these physics teaching lens can stimulate students' cognitive ability in physics, giving you more convenience. Features -Color:Transparent -Material:Acrylic -Size:2.50X2.50X0.20cm/0.98X0.98X0.08in - Made of good 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. - Practical teaching tools whether for students to learn about the properties of light or for teachers to conduct teaching. Package list: 60 x optical lens