DIN 908-1992
Hexagon socket screw plugs
DIN 906-1992
Metric hexagon socket pipe plugs
CNS 4847-1982
Hexagon socket pipe plugs with shoulder and parallel thread
CNS 4848-1982
Metric hexagon socket pipe plugs with taper thread
JB/ZQ4444-1997
Hexagon socket pipe plugs with shoulder and parallel thread
JB/ZQ4444-2006
Hexagon socket pipe plugs with shoulder and parallel thread