PolySwitch will protect against electrical (current) overload and will protect speakers in most situations. They are not foolproof and will not protect against mechanical overload. Select the device based on its trip (power rating in watts). For example, you need to protect a tweeter that will handle 10 watts RMS and its rated at 8 ohms you would select an RXE075 device. If in doubt, be conservative. Some experimentation may be necessary since music signals can vary a great deal. Simply connect in series with the speakers you wish to protect.

When the operating current of the protector is exceeded the interior of the device partially melts, which suddenly increases the volume which increases the resistance drastically. This in turn reduces the current. The device stays in this state while the current is maintained because its temperature is elevated. Once the current is removed, the device re- establishes itself almost immediately, so that the low resistance value is restored.