Starrett 79A-4 Solid Nut Outside Spring Caliper, Steel, Flat Leg, 0-4" Range
Starrett "Yankee" Calipers are made from a high-grade steel and well-finished.  The legs are made of flat stock and are very durable.  The fulcrum stud is hardened and has a smooth bearing surface.  The bow string, although flexible, is exceedingly strong