LX-4 Donegan OptiVISOR has lightweight acylic lens vs glass lenses on the DA-Series, this is a hands-free, headband binocular magnifier that has 2x lightweight acrylic lens vs the normal glass, the acrylic lenses are ground and polished into prismatic lenses for quality and clarity, and provides a focal length working distance of 10" other lenses are available in varied magnification which provide specific magnification power (X) at specific focal lengths, or distance from object. The Donegan OptiVISOR is considered by many to be the finest headband magnifier available and has been made in the USA for many decades and is highly durable and widely used in industrial and commercial applications. The OptiVISOR 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. Can be worn over eyeglasses and many safety glasses. Our standard size glass lenses available on this site will also fit this OptiVISOR® Brand as well as many other headband magnifiers.