Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 6403-122 found under Coupling Shaft Flex by Electro Switch Corp. The National Stock Number assigned to this part is 3010002882650, and the Federal Supply Class is 3010 Torque Converters And Speed Changers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 6403-122.