Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2503221C1 found under Filter Element Fluid by Navistar Intl Corp. The National Stock Number assigned to this part is 4330015074201, and the Federal Supply Class is 4330 Centrifugals Separators And Pressure And Vacuum Filters. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 2503221C1.