LED Building Wiring Fault Indicator - This LED informs users of potentially dangerous wiring problems in the wall circuit. Always on Outlets - 8 outlet models offer dedicated space to accommodate wide transformer blocks without covering adjoining outlets and 2 always on outlets. You can plug 8 power cords including 3 transformers at the same time. In case you have equipment that has to stay on all the time, such as fax machine, you can plug it in always on outlets. The equipment will be protected and will have power supply even when the unit is switched off. Catastrophic Event Protection - SurgeArrest components such as MOVs and Thermal fuse ensure instantaneous reaction to lightning strikes and wiring faults. If the surge components are damaged due to power spike or over voltage, excess power cannot reach your equipment. Unlike the APC SurgeArrest products, most surge suppressors continue to let power through even after circuits have been damaged, leaving your equipment exposed to other damaging surges. 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. Lightning and Surge Protection - To prevent damage to your equipment from electric power surges and spikes. Data-line Protection - Protection of data lines (Ethernet, Coaxial and Phone lines) ensures complete protection of your equipment from surges. It is very important to protect your equipment from “back door” electric surges traveling through data lines, as they can be as damaging to your equipment as surges traveling over power lines. 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.