Will automatically start boosting 10% if the voltage drops to 113 or below down to a minimum of 90V. If the incoming voltage is 114V or higher, you will have only a 2% boost. Advanced surge protection built in! The unit offers 2,400 joules of surge protection and constantly monitors incoming power to protect against spikes or surges. Replaceable Surge / Spike Module should you get hit by a large spike, no need to replacing the entire unit. 2,40030A joules of advanced surge protection. Fully Automatic 10% boost when needed. TKeep out of heavy rain/water. Complete LED Diagnostics ensure you are aware of any hazardous park power conditions and any faulty wiring. Boost indicator light. Voltage Booster & Surge Protection all in one!. Free Security Cable Lock to help prevent theft.