Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 661 5B PC 6 found under Retainer Ring Valve by Flowserve Corporation. The National Stock Number assigned to this part is 5365012312868, and the Federal Supply Class is 5365 Bushings Rings Shims And Spacers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 661 5B PC 6.