The Waldmann 138-442-001 RLLE-122 Ring-Light Magnifier with Clamp Base is a conventional approach to magnification and inspection lighting. It provides 4-diopters of magnification and the most rugged construction of any "Ring Magnifier" in the industry. There is an optional snap-in Add-X lens to increase magnification. It's ideal for inspection applications requiring bright light and strong magnification in a compact, round magnifier. Included with the 138-442-001 is an energy-efficient electronic ballast and acrylic lens for smooth, diffuse light. This high-quality, optical-grade magnifier is distortion-free and has an industrial grade arm with hidden springs and lockable pivoting joints to provide precise positioning and adjustment. The arm mounted switch allows for easy access and one-handed operation.