DS EN 3543:1997 Aerospace Series - Screws, 100 Degree Countersunk Normal Head, Offset Cruciform Recess, Close Tolerance Normal Shank, Short Thread, In Heat And Corrosion Resisting Steel, Passivated - Classification: 1100 Mpa (At Ambient Temperature)/425 Degree C Defines the characteristics of screws, 100 degree countersunk normal head, offset cruciform recess, close tolerance normal shank, short thread, in heat and corrosion resisting steel, passivated.