The self-locking elements while covered by this specification are intended to be incorporated in external or internal screw threads to be used in applications where maximum temperature does not exceed 250°F. When these self-locking elements are incorporated in external threads and are used in compliance with MS15981, all the configurations of Figure 1 are interchangeable. A specific type should-be specified only when required by design or application requirements. Lubrication of the fastener containing a self-locking element per this specification is not recommended because the lubricant may reduce the minimum breakaway torque.