Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number LL-1554 REV B ITEM 9.5 found under O Ring by Olmsted Products Company Llc. The National Stock Number assigned to this part is 5331001660968, 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 LL-1554 REV B ITEM 9.5.