Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4W 33551 6 found under Washer Flat by New Philadelphia Fan Co Buffalo. The National Stock Number assigned to this part is 5310013665147, 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 4W 33551 6.