 In one extremely high-density configuration, the array takes the form of a ring containing hundreds or thousands of individual pogo pins; this device is sometimes referred to as a "pogo tower".They can also be used for more permanent connections, for example, in the Cray-2 supercomputer.When used in the highest-performance applications, pogo pins must be very carefully designed to allow not only high reliability across many mating/unmating cycles but also high-fidelity transmission of the electrical signals.