The General tools 452-6 flat leg machinist outside caliper will help you measure the external size of many objects to help you complete your tasks. It includes a hardened and tempered bow spring and a fulcrum spool that assures constant tension. This General caliper also has an adjusting screw with a self-seating washer and nut for quick and positive changes. It is made from forged steel and features a hardened measurement face for optimal performance.