Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number PR50-18-4 (OXY CLEAN found under Valve Regulator Div by Circor Aerospace Inc. The National Stock Number assigned to this part is 4820014728862, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like PR50-18-4 (OXY CLEAN.