The Diamond Estimator Scale Loupe is the perfect professional gemologist tool for quickly measuring the size/weight of diamonds both set and unset. This 10X triplet loupe features a 18mm-dia. lens with a clear built-in layer that is printed with both a linear scale (12mm/6.5 ct.) and circumference scale for round diamonds (0.5–3.5mm in 0.5mm increments). The quality European made 18mm lens is both aplanatic and achromatic with an anti-reflection coating to minimize glare and light interference. This precision loupe has adjustable focus and a comfortable textured grip. The housing of the loupe is solid-grade aluminum with a scratch-resistant coating. Comes supplied in a protective padded box with zipper closure and a fitted die-cut foam lining.