Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ERT2A503K found under Resistor Variable W by Carleton Technologies Inc. The National Stock Number assigned to this part is 5905005427805, 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 ERT2A503K.