The Bilstein PSS 9 Suspension is the only suspension allowed under the BSR rules, but the POC made a great choice in selecting them for the class. The fully-adjustable monotube gas shock absorbers offer a selection of nine precise compression and rebound settings, from comfort to competition. Patented digressive piston head design and deflective valving instantly reacts to changing road conditions. Monotube design dissipates heat more effectively than a twin tube shock for cooler, more efficient operation and longer life. The front and rear progressive rate springs allow accurate adjustment of the vehicle ride height and center of gravity for the level of performance you seek. The PSS 9 system puts you in complete control.