Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 57A00-109 found under Coupling Shaft Flexible by Sierra Networks Inc. The National Stock Number assigned to this part is 3010007666537, 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 57A00-109.