American "A" Brass Nut LH Fuel Gas 3/8" x 24 UNF
This is the very small connection nut used for the micro torch systems on American blowpipe inlet connections.
Brass nut with 3/8" x 24 TPI UNF thread form.
Nut AF 11mm
Nut length - 12mm
Thread depth - 9.5 mm