Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B20500-2 found under Washer Lock by Allied Signal Inc. The National Stock Number assigned to this part is 5310000106496, 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 B20500-2.