SpeedTek RC hardened stainless steel spool shaft, bearings (2) and cups (2) kit that fits in the Arrma 6S Models including Limitless V1 & Felony 6S !  Does not fit in the V2 Limitless. The center driveshafts are the incorrect length.
 
We use these spools on all of or drag racing & speed run vehicles. The high speed spool kit comes with a 8mm hardened stainless steel spool, hardened steel drive cups and hybrid shielded bearings.