This document contains dimensional and technical requirements of prevailing torque type all-metal hexagon nuts with flange and specifies their designation.
DIN EN 1664:1998 history
1998DIN EN 1664:1998-02 Prevailing torque type - All-metal hexagon nuts with flange (ISO 7044:1997, modified); German version EN 1664:1997
1998DIN EN 1664:1998 Prevailing torque type - All-metal hexagon nuts with flange (ISO 7044:1997, modified); German version EN 1664:1997