• Black color headband binocular visor with three magnifying lens plates for hands-free viewing.
• Interchangeable lens plates provide 3X, 4X, and 5X magnification.
• Optical-grade acrylic prismatic lenses for improved focus and reduced eye strain.
• Visor tension-adjustment knobs allow visor to tilt out of way when not needed.
• Can be worn over prescription or safety eyeglasses.

The Donegan OSC Opti is a hands-free, headband binocular magnifier that has an optical-grade, acrylic lens ground and polished into a prismatic lens, and is available in multiple dioptric strengths which provide a specific magnification power (X) at a specified focal length, or distance from 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 OSC Opti magnifier features replaceable binocular lenses that have beveled edges, and are ed 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. The magnifier can be worn over prescription or safety eyeglasses. A durable, plastic visor tips up above the forehead when not in use. Spring-loaded pivot screws hold the visor in a raised or a forward-facing position. The magnifier comes in assorted body colors such as black, and blue. The magnifier weighs 0.58 lbs, and comes housed in a protective shell and carrying case. It has 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) decrease. Magnifiers and prescription eyeglasses have a diopter value, such as 1.5 or 2. The dioptric strength of an accessory lens, such as prescription eyeglasses or an eye loupe, must be added to the dioptric strength of the magnifier to calculate total magnification. Magnifiers are devices used to the visual appearance of an object or image. Magnifiers 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. Magnifiers are commonly made of plastic or glass. They can have one or more lenses with varying magnification abilities, and can have a binocular configuration with a single lens, or two separate lenses. They are sometimes used with LED or fluorescent light sources to help control viewing capabilities. Magnifier ability is often expressed as magnification at a specific length. For example, 1.75X at 14” means that when a magnifier is held at 14” from a viewer’s eyes, the object will be magnified 1.75 times (X) its actual size. As magnification increases, viewing areas and focal length decrease. Magnifiers sometimes have a diopter number, expressed as + or - D, which is a measurement of strength (or power) of the lens. Some magnifiers are marked with a dioptric number on the lens. A high diopter number has a higher magnification than a low diopter number. Aspheric magnifiers, unlike spheric magnifiers, Determining Magnification ------------------------- Diopter Magnification Focal length (Distance from object) Sample view 20/20 vision 20" (50.8cm) 2-diopter lens 1.50X 20" (50.8cm) 3-diopter lens 1.75X 14" (35.56cm) 4-diopter lens 2.00X 10" (25.4cm) 5-diopter lens 2.50X 8" (20.32cm) 7-diopter lens 2.75X 6" (15.24cm) 10-diopter lens 3.50X 4" (10.16cm) offers less distortion. Magnifiers are widely used in jewelry inspection and fabrication, watch- making, needlework, artwork, reading, print inspection, and stamp-collecting. 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? * OSC Opti magnifier * Fitted, plastic, carrying case * Instruction manual