Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BN672 M4 found under Washer Lock by Bossard Ltd Fasteners. The National Stock Number assigned to this part is 5310121459279, 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 BN672 M4.