Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number STD 2231 found under Ring Retaining by Textron Lycoming Inc. The National Stock Number assigned to this part is 5325016218352, 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 STD 2231.