Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HS5518-4 found under Light Cockpit Aircr by Boeing Company The. The National Stock Number assigned to this part is 6220014548280, and the Federal Supply Class is 6220 Electric Vehicular Lights And Fixtures. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like HS5518-4.