Octura Flex Hex Coupling – 1/4-28 x .187 (fits KB .21-.67 has pilot to match recess in flywheel)
For coupling flexible cable to threaded nitro engine crankshaft. The base of the flex hex threads onto the motor output shaft – the cap tightens flex hex around the cable like a collet in a drill chuck) – Do not use with squared end cable. Do not use with solid drive shafts. If you need to connect to a solid drive shaft, use a universal.