Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 28-31 found under Tire Propeller Nut by Walz And Krenzer Inc. The National Stock Number assigned to this part is 2010010603677, and the Federal Supply Class is 2010 Ship And Boat Propulsion Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 28-31.