Swing Arm Lighted Bench Magnifier Jewelers Opti Tool This is a new 5X black, illuminated swing arm magnifier with clamp on base The powerful magnification may help to reduce eye strain The lens measures approximately 4" (102 mm) in diameter It is convenient for your home or office and enlarges fine print in books, maps, newspapers, directories, legal documents, etc. It is ideal for reading assistance in low-light conditions 118-120V 60Hz