Protect your appliances from surges in high voltage. Whether there is a power outage, unstable power supply, or other electrical incident, this will protect your appliances from short circuiting. This device has a 4 minute safety cycle in order to make sure voltage levels are stable before directing power to your appliance. This is great for most appliances such as air conditioners, refrigerators, freezers, washing machine, etc. In extreme circumstances with ultra high voltage, this device will self destruct in order to preserve your appliance. There is also a convenient alarm that will sound when the power shuts off to your appliance, so that even if it is hidden behind the refrigerator, you can hear when it kicks in.