Metric(class1,2,3) Unified,Thread,Parallel Pipe (PF)
Screw this gauge in a worked thread by hand smoothly,GP,GR must go through over the whole length of thread.
Screw this gauge into a worked thread smoothly by hand.WP,WR,IP,IR,shall not be screwed in more than two revolutions included two revolutions,from either sides.
GR shall not go through from either side when screwing this check plug by hand smoothly.
IW,WW shall not go through from erther side when screwing this check plug by hand smoothly.