Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MSC 503K found under Resistor Thermal by Rtie Holdings Llc. The National Stock Number assigned to this part is 5905003684081, 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 MSC 503K.