This compact diamond seller is used to show the sizes of brilliant cut diamonds. Each stainless steel alarm is set with cubic zirconia and marked with the size and carat weight. Easy to use and read, the tool shows 10 sizes ranging from 0.1 karats to 2 karats and it falls within a protective cover when not in use. See this diamond seller and more handy Gemological tools at Stuller.com/tools.