[PORTABLE SURGE PROTECTOR] The YOMILE 50A RV Surge Protector offers 12800 Joules of surge protection and features an adapter circuit analysis instrument to identify faulty power and detect connection errors. [CIRCUIT ANALYZER] Prior to connecting your RV, use the 50A RV Circuit Analyzer Diagnostic Chart to test the quality of your power and identify most wiring faults, including Correct Wiring, Open Ground, Open Neutral, Reverse Polarity, hot/Ground Reversed, and No Power. [SAFETY IS THE FIRST] The camper surge protector is FCC tested and made of V-1 flame-retardant materials, with an IP67 waterproof design and protective cover to safeguard against rain, wind, and sandstorm. [EASY TO READ] The surge protector RV 50 amp built in 3 indicator lights, when two green lights are on simultaneously, it indicates that the wiring method of the RV power supply is correct, otherwise it is a fault: open ground, reverse polarity, and so on. It is reassuring to have the lights to confirm the campground grid is safe to use. [Easy to Use]The RV Surge Protector's plugs are designed with ergonomic power grip handles to safely and easily plug and unplug it, featuring a right-angle male connector to provide a reliable low-damage and low-bend interface with your power source. Portable Surge Protection: The Yomile 50A RV Surge Protector offers 12800 Joules of surge protection and features an adapter circuit analysis instrument to identify faulty power and detect connection errors.