Donegan DA-3 OptiVISOR Headband Magnifier, 1.75X Magnification

The Donegan OptiVISOR is a hands-free, headband binocular magnifier that features optical glass lenses, ground and polished into prismatic lenses for quality and clarity. It is available in multiple dioptric strengths, indicated by the number in the model, which provide specific magnification power (X) at specific focal lengths, or distance from the object. This magnifier enhances the size and resolution of an object or image, and is commonly used for a variety of applications such as jewelry-making, watch-making, needlework, artwork, electronic inspection, book-reading, print inspection, and stamp-collecting.

The OptiVISOR magnifier's replaceable binocular lenses have beveled edges that are mounted in an interchangeable plastic frame. An adjustable headband with a padded leather comfort band conforms to a variety of head sizes and provides comfort for hours of continuous use. It can be worn over prescription or safety eyeglasses, and a durable, plastic visor tips up above the forehead when not in use. Spring-loaded pivot screws hold the headband in a raised or a forward-facing position. The magnifier weighs 0.67 lbs. and comes housed in a protective shell and carrying case, with a one-year limited warranty.

Diopter (D) is a technical term for the measurement of the light curvature and thickness of a lens. A dioptric number and a magnification number are not the same thing. Diopter strength represents a specific magnification power (X). For example, a 5-diopter provides 2.5X magnification (at a distance of 8"). The higher the diopter, the more magnification a lens can provide. As magnification increases, distance to the object (focal length), and field of view (diameter, or narrowness of view) decreases.

Magnifiers are devices used to enlarge the visual appearance of an object or image, and come in a variety of styles such as hand-held, headband, standing, clip-on, eye loupe, and those that hang in a necklace form or fit in a trouser pocket. They can be made of plastic or glass, with one or more lenses of varying magnification abilities, and can have a binocular configuration with a single lens or two separate lenses. Some magnifiers are used with LED or fluorescent light sources to help control viewing capabilities. Magnifier ability is often expressed as magnification at a specific length, and as magnification increases, viewing areas and focal length decrease.

Donegan Optical manufactures and distributes precision visual devices for hobbyists and professionals in industry, home, office, and crafts applications. The company was founded in 1952 and is headquartered in Lenexa, Kansas.

What's in the Box? - Optical Glass Binocular Magnifier - 1.75x magnification with a focal length of 350mm (14") - A precision instrument that improves vision and increases your efficiency - Fully adjustable to fit any size, quickly and easily - Interchangeable lens plates are available (sold separately)

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