Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B1-20 found under Screen Window Metal by Edwards O M Co Inc The. The National Stock Number assigned to this part is 5670002447323, and the Federal Supply Class is 5670 Building Components Prefabricated. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like B1-20.