This Standard covers the general, dimensional, mechanical, and performance data for metric prevailing-torque hex nuts and hex flange nuts of property classes 5, 9, and 10 as defined in ASTM A563M. The inclusion of dimensional data in this Standard is not intended to imply that all of the nut sizes in conjunction with the various options described herein are stock items. Consumers should consult with suppliers concerning lists of stock production prevailing-torque hex and hex flange nuts. B18.16M-2004 is a consolidation and update of B18.16.1M-1979, B18.16.2M-1979 and B18.16.3M-1998.