All tabulated size ranges are inclusive. All standard-length pin gages over 0.060” (1.51mm) are laser marked with size, class, and direction of tolerance. Note: Standard Class Z are 2” in length with the diameter available in 0.0005” (0.01mm) increments. All gages are made of 52100 steel. Tolerance direction: GO (Plus) or NOGO (Minus)