Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2 1 2HH A223 ITEM NO 25 found under O Ring by Sheffer Corp. The National Stock Number assigned to this part is 5331014186757, 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 2 1 2HH A223 ITEM NO 25.