Isolators are usually specified by their static deflection D, or how much they deflect when the
weight of the machine is placed on them. This is equivalent to specifying their stiffness and has
the additional benefit of making it easy to calculate the system natural frequency. Coil spring
isolators are available in up to 3” static deflection. If more flexibility is needed, air springs are
used. The natural frequency of the system (assuming a single degree of freedom) can be
calculated by: