The 80-0050 is a AC power duplex surge module designed to provide protection against short term over-voltage conditions as well as from RFI (radio frequency interference). Surge protector outlet alerts you to the failure of the surge protection component by means of an audible signal. If alarm sounds, device has “received” power surges in excess of its capacity and is no longer functioning as a surge protector. To shut off alarm, simply turn the “Alarm Off” screw on the front of the outlet clockwise. Note: When alarm sounds and the “Alarm Off” screw is turn off, the outlet still functions as a normal duplex outlet without surge protection.