Precise dies and dieheads are manufactured on CNC machines. Sets are the lightest drophead available and come in compact, reinforced plastic carrying case. Dropheads available from 1/4in to 2in NPT. Dropheads in these sets fit Reed?s 601PD. Heads up through 11/4in are interchangeable with RIDGID? brand 11-R and R200, Super-Ego? 600, Virax? 1362, RothenbergerTM Super Cut hand ratchet threaders and Supertronic portable power threaders.