DS EN 4119:2005 Aerospace Series - Nuts, Bihexagonal, Self-Locking, Deep Counterbore, In Heat Resisting Steel Fe-Pa2601 (A286), Silver Plated On Thread - Classification: 1100 Mpa (At Ambient Temperature)/650 Degrees C Defines the characteristics of self-locking bihexagonal nuts with deep counterbore in FE-PA92HT, silver plated on thread, for aerospace applications.