Features It is made of premium K9 glass ,crystal clear,with great Optical performance. It is coated with anti-reflection film on the double sides. It can be used for Physical Optics experiment lens. It has 2.5 X magnifying factor,for diy magnifying lens. 100% brand new product, all refund if unsatisfied If you have any questions, please contact our professional customer service team. Features: -It is made of premium K9 glass ,crystal clear,with great Optical performance. -It is coated with anti-reflection film on the double sides. -It can be used for Physical Optics experiment lens. -It has 2.5 X magnifying factor,for diy magnifying lens. -100% brand new product, all refund if unsatisfied If you have any questions, please contact our professional customer service team.   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