Description This set of physics teaching toolis made of premium glass, safe and durable.It can help students learn and understand more specifically how to find the principle of light refraction. Thus, students can understand this physics principle faster. Features -Color: Transparent -Material: Glass -Size: About 6x3x1cm / 2.36x1.18x0.39in - This item is a set of option experimentmodel, which is a good tool for teaching. One-piece molding, the standard is flat and smooth -Digital control processing technologyand precise sizecan ensure the accuracy of the optical experiment. -The storage box packaging is convenient to take and carry. -A variety of lenses to meet the needs of the experiment, it provides convenience for both teachers and students. -Preferential price and reliable quality, the best optical experiment tools for teaching.Package list: 5 x Optical lens