Starrett 77B-6 Fay-Spring-Type Dividers, Quick-Spring Nut, 6"/150mm Leg Length The Starrett quick-adjusting automatic-closing spring nut is designed for making quick, positive adjustments Strong and flexible bow spring adjustment screw is centrally located in the legs to assure smooth action The legs are made from heavy square stock, machined to a smooth taper The fulcrum stud is hardened and has a large bearing surface to prevent side deflection of the legs