Optical glass lens, laboratory optical bench accessory Science experiment - exploring optical property, Early physics science educational toy for kids children student Student pupil teaching Aidsthe fun of the lenses learning science knowledge kid science development toys, a series of physical science boarden kids and children , stimulating their curiosity Material: Optical Glass, Plastic Frame ColorAs picture show Size Chart: Convex Lens Diameter: 40mm Focal Length: 100mm Handle length : 13.5cm/ 5.31 inch Package Includes: 1 piece Optical Glasses Len Toy (2 Pack) Note: Please allow 1-3mm error due to manual measurement, make sure that you do not mind before you bid. Due to the different monitor and light effect, the actual color may be slightly different from the picture color.