The #331 Robert Sorby 5/16''-8 mm Sash Mortice Chisel is a vintage original tool made in Sheffield, England. Known for their high quality craftsmanship, Robert Sorby is a respected brand in woodworking and carpentry. This specific chisel is designed to create precise and clean mortices for sashes in a 5/16'' to 8 mm range, making it a valuable addition to any collector's or craftsman's workshop.