THE LEITECH-US THREAD PLUG GAGE IS A PRECISION GAUGING TOOL. THE MODEL IS THREAD PLUG GAGE. THIS ITEM IS A 1/2-20 UNF 2B DEPTH THREAD PLUG GAGE. THE LOT INCLUDES TWO OF THESE GAGES WITH SPECIFIED PITCH DIAMETERS (PDS) OF .4675 AND .4731. THIS TOOL IS DESIGNED FOR PRECISION GAUGING APPLICATIONS.