Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 448 16403 found under Washer Flat by Jcb Inc. The National Stock Number assigned to this part is 5310016685557, 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 448 16403.