Cane Creek Double Barrel Air CS Rear Shocks. CS is a selectable climbing mode on Double Barrel shocks that adjusts both low speed compression and low speed rebound. By selectively tuning both compression and extension phases when climbing, the shock maintains traction and control while enhancing pedaling efficiency through the shock's entire travel. It does this by turning on and off a set of internal 'climbing circuits' that are accessed when CS is engaged. When the rider is ready to descend, with the flip of CS, the shock returns to the traditional low-speed circuits of the Double Barrel.