The RSH-120 is a surge protector for the entire home, and is meant to be installed at the breaker panel. The RSH-120 uses Gas Discharge Tube Technology along with Thermally-Fused Metal Oxide Varistors for ultimate protection. Features Designed to protect electrical appliances in the home from damaging power surges and spikes Dual Diagnostic LEDs and audible alarm Gas Discharge Tube Technology and TFMOVs Type 1 SPD, NEMA 4X and IP66 rated Limited Lifetime Product warranty