Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ACR 050-4MM-5 found under Coupling Shaft Flex by Helical Products Company Inc. The National Stock Number assigned to this part is 3010013835077, 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 ACR 050-4MM-5.