DS EN 4125:2010 Aerospace Series - Nuts, Anchor, Self-Locking, Fixed, Two Lug, Reduced Series, With Incremental Counterbore, In Heat Resisting Steel, Mos[2] Lubricated - Classification: 900 Mpa (At Ambient Temperature)/315 Degrees C Defines the characteristics of self-locking two lug, reduced series, incremental counterbored fixed anchor nuts, in heat resisting steel, MoS[2] lubricated.