Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1U31989-03 found under Plug Protective Nozzle by Atk Launch Systems Inc. The National Stock Number assigned to this part is 1420007524130, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 1U31989-03.