Starrett 73A 6 Solid Inner Spring Saddle, Steel, Flat Left, 0 Inch Range

Starrett Inner buttons are made of high-quality steel in the best workmanship. The flat legs are extremely stable. Hardened swivel pin with smooth contact surface. The flexible, but also stable, bow spring. Quick adjustment, auto-locking spring nut for secure adjustment. The thread of the nut engages in the screw even at the slightest pressure of the legs. Once the pressure is missing, the nut releases the screw again and can be moved as desired. This saves time for locking and loosening the nut.