A nitrogen-charged (or air) bumpstop consists of a short stroke shock mechanism that is velocity-sensitive. Oil is used inside and moves through orifices much like a standard shock. This allows the bump to effectively dampen, or slow, the suspension movement through its final inches of travel. The hydraulic action offers a smooth exponential rising rate of resistance as the bump is compressed. This eliminates that hard, sudden end of travel you often experience with a fixed-material bumpstop. Air bumps also exhibit some rebound damping, as well.