APC P4V Audio/Video 120V Surge Protector 4 Outlet with Coax Protection. Audio-video power protection from damaging power transients Building Wiring Fault Indicator - This LED informs users of potentially dangerous wiring problems in the wall circuit Protection Working Indicator - SurgeArrest will warn you if its circuitry has been damaged by heavy strike or power line surge and it is unable to provide 100% protection. If still under warranty, APC will then replace your damaged SurgeArrest free of charge Fail Safe Mode - Most other surge suppressors continue to let power through even after their circuits have been damaged, leaving your equipment exposed to future surges. APC's SurgeArrest fail safe, which means that once the circuit of an APC SurgeArrest has been compromised the unit disconnects equipment from the power supply ensuring that no damaging surges reach your equipment Transformer Block Spacing - Connect bulky transformer block plugs without covering up other outlets