Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1K4011S020 found under Insert Flexible Coupling by Senner Karl Inc. The National Stock Number assigned to this part is 3010015308491, 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 1K4011S020.