Bresser National Geographic 3x, 35x40mm is a convenient magnifier with built-in LED illumination and reliable sliding design. To turn the illumination on, just slide two pieces of the frame apart; and to turn it off, slide them back together. The illumination is powered by two CR-1130 (3V) batteries included in the kit. This magnifier produces 3x magnification that is high enough to help you read small print in newspapers, on product labels, etc. The lens’ dimensions are 35х40mm. The frame is made of lightweight plastic that is safe for the environment.