Red Binoculars in ABS plastic. Supplied with neck straps and cover lens equipped with a blocking system on the lens to prevent loss. The variable interpupillary distance (from 49 to 78 mm) permits correct use even by children. Technical: Objective lens: diameter 40 mm Optics: 4 elements Magnification: 3.5 times Focus regulation with central micrometric screw Regulation of the interpupillary distance Ages 5 and up Made in Italy Brand name: Navir What is an objective lens? The objective lens is used to form an image to be viewed. It is at the front of the binoculars. In general the larger the objective the more light can be collected therefore the more defined the image, even in poor light. As an alternative, the Navir Yellow Binoculars have a 40mm objective lens and produce a sharper image and come packed in a yellow case.