Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 639-0006 found under Washer Flat by Bae Systems Information And Electronic Systems Integration Inc. The National Stock Number assigned to this part is 5310012896665, and the Federal Supply Class is 5310 Nuts And Washers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 639-0006.