Identify bolts, fittings, pipe threads and spark plugs with either US standard or imperial, metric threads.
Soft aluminum won’t damage threads of fine parts.
Holes in gauge allow easy identification of component sizes.
Gauge allows quick identification of thread pitch or threads per inch.
Identifies both thread diameter and pitch.

Sizes measured are:
US standard thread sizes from #5 to 3/4” and pitch of 10 TPI to 44 TPI.
Metric threads sizes from 2.5mm to 22mm and pitch of 0.45mm to 2.5mm.
Pipe thread sizes 1/16” to 1/2” with 14 TPI to 27 TPI.
Spark plug thread sizes 10mm to 18mm.