DS EN 3637:2008 Aerospace Series - Nuts, Self-Locking, Bi-Hexagonal (Double Reduced), In Heat Resisting Nickel Base Alloy - Ni-P101ht (Waspaloy), Silver Plated, Classification: 1210 Mpa/730 Degrees C Defines the dimensions of self-locking, silver-coated bi-hexagonal nuts with MJ-thread in heat resisting nickel base alloy NI-P101HT for aerospace applications.