Features 2.5 X Magnifying Factor: The optical convex lens has 2.5 X magnifying factor,for diy magnifying lens. It can be used for Physical Optics experiment lens. Premium K9 Glass Material: The optical glass convex lens is made of premium K9 glass ,crystal clear,with great Optical performance, it is coated with anti-reflection film on the double sides, sturdy, not easy cracked, can be used for a long time. Excellent Performance: The convex lens is processed by professional manufacturing, it has precise design, waterproof and dust prevention, stable performance. Easy to Install: The K9 glass convex lens is easy to install and convenient to use, can directly replacement for the old or broken one. Quality Assurance: The magnifying glass lens is manufactured under strict quality control and standard requirements, and has a high safety factor, so it can be used with confidence. Specification: Diameter: 30mm / 1.2in Focal length: 100mm / 3.9in Center thickness :5mm Edge thickness: 2.8mm R = 15 mm Material: K9 optical glass Double coated with anti-reflective film Magnification: 2.5 times Package list: 1 x Double Convex Lens     Package List