One Side Measures Your Stones In Carats (,02 To 6 Carat), The Other Measures Your Pearls In Grains (1/2 To 40). Metric; Made Of High Impact Plastic.* Made Of Durable Plastic * One Side .02-6 Carats * Other Side: 1/2 To 40 Grains * Metric Measuring Scale * Accurate & Professional