Trusted by professionals, easy enough for beginners. Each bottle contains 1/2 fluid oz (0.5 fl oz) test acid. Test stones are brand new, and will last many uses; extra large stones measure 6 inches x 3 in.; the standard size (small) stones are 2in x 2 in. DigiWeigh 600 x 0.1g DW600BX digital pocket scale is ideal for weighing scrap jewelry, even gemstones, parts for model-building, coins, gold bars, silver ingots, small postal shipments & much more. This scale enables you to choose between four modes: Grams (g), Ounces (oz), Troy Ounces (ozt), and Carats(ct). Scale Capacity x Accuracy: 600 x 0.1 g, 21.2 x 0.005 oz, 19.2 x 0.005 ozt, 386 x 0.1 ct. Very easy to use. Culti Diamond Selector II testing machine emits audible sound & shows GREEN light for accurate reading. LCD display & LED indicator. If stone is fake, i.e., crystal or some other simulant such as cubic zirconium (CZ), there will be no reaction. Buzzing indicates when the tester touches metal rather than stone; includes 60-day money back guarantee. Gemstone weight gauge included too. Popular among professionals, hobbyists, coin enthusiasts, business owners, and students alike. Excellent tools. Excellent Value.