It has been shown that at cryogenic temperature crystallographically oriented chips of single crystal Ti2O3 behave as transient suppressors with high switching speeds, low trigger-voltages and high current capacities. Switching times are of the order of a few nanoseconds. Further, it has been shown that crystallographically oriented chips of single crystal NbO2 behave similarly, but at room temperature or even higher. Here, however, switching is slightly slower and contact problems have yet to be elucidated. A new theory has been developed which explains the results and suggests a whole class of materials to draw from.