Clocksmiths SE Jeweler's Loupe - 30X - Watchmaking Jewelry Supplies Doublet lens loupe made of high-quality optical glass with case Round swing-away chrome plated handle 30X power and focal distance of 0.5" Lens diameter is 21 mm Does not include the chain-necklace in primary photo, but a raised loop on the exterior of the magnifyer enables you to attach any chain or string of your choice