This International Standard specifies the dimensions of self-locking, fixed, two lug anchor nuts, reduced series, with counterbore, with MJ threads, of classifications: 1 100 MPa 1)/235 °C 2), 1 100 MPa 1)/315 °C 2) and 1 100 MPa 1)/425 °C 2). This International Standard is only applicable for the compilation of aerospace product standards.