Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number N-999-6301-B-005 ITEM 31 found under O Ring by Carver Supply Inc. The National Stock Number assigned to this part is 5331010060318, 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 N-999-6301-B-005 ITEM 31.