This is a revolutionary diamond gauge that estimates the carat of a stone set diamond. It is very convenient for negotiating and dealing with the approximate carat of round brilliant cut, pear shave, oval, emerald or square cut. Round cut 0.01 to 3.0 ct (19 types) Pear Shave Oval Emerald Square Cut 0.25 to 1.0 ct (4 types) Ruler 0 to 80 mm Memory Stainless Steel Dimensions 54 x 84 x 0.3 mm with Vinyl Case