The Durston Hardened Rectangular Ring Mandrel is made from premium tool steel, hardened to 64 Rockwell, and ground and polished for precise ring shaping. It features a non-marking tapered design with an ergonomic handle for a comfortable grip and support during use. The mandrel is available in sizes ranging from 6.5 x 8.5 mm to 18 x 23 mm and is suitable for shaping rectangular or oval rings. It is designed to create consistent, superior ring shaping for professional jewelers.