Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number NMP-1521 PIECE 16 found under Ring Retaining by Keystone Intl Inc. The National Stock Number assigned to this part is 5325012852130, and the Federal Supply Class is 5325 Fastening Devices. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like NMP-1521 PIECE 16.