A laptop computer is an example of an end product that requires multiple forms of circuit protection because of the multiple data connections. The USB port alone contains multiple lines requiring protection. For example, if a faulty USB cable is plugged into the USB port, the applied voltage, polarity, and permitted current may exceed the limit of the power regulation circuits. Or, an ESD spark can find its way into the sensitive electronics through the USB datalines. A PolySwitch device can limit the flow of high currents, while a PESD device clamps the ESD voltage to a safe level.