Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 561-515-0012 found under O Ring by Du Pont E I De Nemours And Co Inc. The National Stock Number assigned to this part is 5331014295102, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 561-515-0012.