To establish a metric module version of the UNJ profile, MIL-S-8879 inch screw thread standard, predominantly used in aerospace inch designs. This standard specifies the characteristics of the MJ profile metric series of screw threads, altered from ISO 68 M Profile, to include a mandatory controlled radius of 0.18042P to 0.15011P at the root of the external thread and with the minor diameter of both external and internal threads increased to provide a basic thread height of 0.5625H in order to accommodate the external thread maximum root radius.