4" diameter with 3 power lens, covers large areas of print. This 4" illuminated magnifier features a powerful 3X lens and a built-in bifocal insert for 5X magnification of extra-fine details. Bulb gives wide circle of illumination. Switchable light aids inspection in poorly lit areas. Plastic body and optical plastic lens. 2 C batteries included. Great for quality control inspections, jewelry making, and electronics assembly. Commonly used in stamp collecting, coin collecting, and model building. Focal length of lens is 3-1/3"; bifocal is 2".