Innovative Components AH-COM Thread Detective / Thread Identifier Inch. and Metric Combo Set with Ruler Attached Set includes both Inch and Metric identifiers. Thread sizes are permanently laser etched on each gauge. All sizes are steel with a clear zinc finish and each gauge identifies both bolts and nuts. Takes the guess work out of thread size and pitch on nuts, bolts , screws, threaded holes and many other threaded items. Eliminates costly and time consuming repairs. Great for identifying and sorting nuts and bolts in fastener cribs, fastener bins at home or at your facility.