Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MC55D1021F found under Resistor Fixed Film by Texas Instruments Inc. The National Stock Number assigned to this part is 5905002594433, 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 MC55D1021F.