Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SFR 4-4OX.31BO found under Screw Machine by Fastbolt Corp. The National Stock Number assigned to this part is 5305014913084, and the Federal Supply Class is 5305 Screws. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like SFR 4-4OX.31BO.