Slot
Hex with flange
Hex with collar
Twill-knurl
ASME/ANSI B18.2.4.4M-1982
Metric hex flange nuts
ASME/ANSI B18.2.4.4M-1993
ASME/ANSI B18.2.4.4M-1999
ASME/ANSI B18.2.4.4M-2005