3M 37001, Combination Dual Airline Back-Mounted Breathing Tube SA-2600/37001(AAD), 7000002044, 1 EA/Case 
Insize 4131-1A1, AMERICAN STANDARD THREAD PLUG GAGE, 1/2-13UNC, 6928640359019
$104.84
Class 2B.
Standard ANSI/ASME B1.2
Supplied with Go and No-Go gages together
Supplied with manufacturer inspection certificate.
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