BelOMO 7x Triplet Loupe Folding Magnifier, High-Quality Optical Glass with Anti-Reflection Coating 7x Magnification Power Large 22mm(0.866'') Achromatic Triplet Lens Gathers Light for a Bright, Clear and Color Correct View Optical Quality Glass Lenses, each BelOMO loupe is certified just like a camera lens. Great for rocks, minerals, jewelery, coins, stamps, part inspection and snow flakes Each screw is treated to prevent its coming loose by Amateur Geologist