The GPM 4140 carbon steel center CVD driveshaft is engineered to reinforce the ARRMA OUTCAST 8S BLX driveline where repeated shock and torque peaks occur. Using medium carbon 4140 steel provides predictable fatigue resistance and stable performance during intensive stunt and racing use. The front diameter increase from 5mm to 6.5mm improves torsional stiffness and reduces drivetrain slip under heavy throttle.