Our round hoop mandrel measures 12", with a threaded rod attachment for hands free use, and is hard chrome plated steel with a highly polished surface and tapers from 3/8" to 2" (10mm to 52mm) for a wide range of rings, earrings, hoops and bracelets, giving it a great variety of uses for goldsmiths, silversmiths, jewelers and bead artists. The weight of solid steel gives it the heft that one needs to more easily work non-ferrous metals. Weighs 4 lbs.