Fresnel Lens. Features: The Fresnel design of the lens provides for reduced weight and wide field of view; and with its large dimensions, this magnifier is a very practical and easy-to-use tool. The built-in illumination means that you can use this magnifier both outdoors and indoors, in daylight or in the dark. A bright LED light is powered by two CR2016 batteries. The lens itself is made of high-quality optical plastic, which is comparable to glass in its magnifying capabilities, yet lighter and sturdier. The metal frame provides for additional durability. Magnification: 2.5x. Diameter: 48/45 mm. Weight: 50 g. The kit includes: Fresnel Lens, 2 CR2016 batteries, Storage case, User manual and lifetime warranty.