Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 500991-25 found under Cap Plug Protective Dust And Moi by Ace Electronics Inc. The National Stock Number assigned to this part is 5340016180537, and the Federal Supply Class is 5340 Hardware Commercial. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 500991-25.