NC American National Coarse
NF American National Fine
NEF American National Extra Fine
8N American National 8 Pitch
NTP American Standard Taper Pipe
NPSC American Standard Straight Pipe
NPTF American Standard Taper (Dryseal)
NPSF American Standard Straight (Dryseal)
UNC Unified Scre Thread Coarse
UNF Unified Screw Thread Fine
UNEF Unified Screw Thread Extra Fine
8UN Unified Screw Thread 8 Thread