385511 Graphite Main Driveshaft M18, M18PRO
385521 Graphite Main Driveshaft M18T, M18MT

Graphite main driveshaft made from top-grade graphite material is a direct replacement for the standard aluminum driveshaft. Lighter rotating mass (55% lighter as the alu driveshaft) results in much quicker accleration and precision balancing gives vibration-free running.

Source : XRAY