Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number X-201-RS503B found under Resistor Variable N by Cts Inc. The National Stock Number assigned to this part is 5905010396630, 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 X-201-RS503B.