DS EN 3686:2008 Aerospace Series - Bolts, Double Hexagon Head, Relieved Shank, Long Thread, In Heat Resisting Steel Fe-Pa92ht (A286), Silver Plated - Classification: 1100 Mpa/650 Degree C Defines the characteristics of double hexagon head bolts with relieved shank and long thread, in heat resisting steel FE-PA92HT, silver plated, tensile strength class 1100 MPa at room temperature.