This is an optional CSI "RED" Mugen MBX7R 16mm Squared V-Port piston set. After rigorous on track testing, as well as using CSI's state of the art shock dyno, CSI engineers have taken 1/8 scale off road shock performance to the next level. CSI squared V-port shock pistons have been re-engineered to deliver superior performance on tracks that produce higher shaft velocities. The Squared V-port pistons provide two separate flow rates for compression and rebound damping. The rebound side of CSI's Squared V-port piston have been engineered to reduce the (packing) effects of the shock when higher velocities are achieved, allowing the tire to return to the surface faster and better absorb the next bump or series of bumps.
CSI Squared V-port pistons are available in two flow rates, the blue base line piston is recommended for average track surface conditions, while the red piston is recommended for rougher track surfaces.