Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 6558 found under Screw Machine by O F Mossberg And Sonsincorporated. The National Stock Number assigned to this part is 5305012544286, 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 6558.