Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number A55 261 found under Retainer Packing by Borgwarner Corp. The National Stock Number assigned to this part is 5330005763022, and the Federal Supply Class is 5330 Packing And Gasket Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like A55 261.