DS EN 3379:1996 Aerospace Series - Bolts, Double Hexagon Head, Close Tolerance Shank, Medium Length Thread, In Heat Resisting Nickel Base Alloy Ni-P101ht (Waspaloy), For Increased Height Nuts - Classification: 1210 Mpa (At Ambient Temperature)/730 Degree C Defines the characteristics of double hexagon headed bolts with close tolerance shank and medium length thread, in NI-P101HT, for increased height nuts, for aerospace applications.