Durston Hardened Ring Mandrels (Round Sizes 10-28) are carefully crafted from the highest quality tool steel, hardened to 64 RC and polished to a smooth finish to ensure consistently superior results. These non-marking tapered mandrels feature ergonomically designed handles for a comfortable grip and excellent support during use. Made for professional jewelers looking for a durable and reliable mandrel designed to accurately measure ring size and shape while minimizing the risk of metal wear or damage.