The document specifies the characteristics of silver plated self-locking serrated shank nuts in heat resisting steel FE-PA92HT, tensile strength class 1100 MPa at room temperature, maximum operating temperature 650 ? These nuts are to be used in aerospace fastening systems mainly stressed in tension when the nut cannot be maintained or fightened with a wrench. Their locking in rotation by serrations prohibits their use in materials or pats which are sensitive to the notch effect.