Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 581573-4 found under Resistor Network Fi by Raytheon Technical Services Company. The National Stock Number assigned to this part is 5905005548230, and the Federal Supply Class is 5905 Resistors. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 581573-4.