This standard establishes the means of assessing the performance of external spline drive wrenching systems for fasteners. The standard defines the Design, Performance and Test Requirements for metric spline drive fastener external wrenching systems. The spline wrench shall be capable of torque loading hexagonal, bi-hexagonal and spline drive fasteners. Fasteners having the spline wrenching configuration shall not be capable of being wrenched with hexagonal and bi-hexagonal wrenches.