PowerGrip RV 50Amp Circuit Analyzer Dogbone w/ Integrated Surge Protection and Indicator Lights helps protect RV from power surges. Diagnostic LEDs indicate wiring faults when you connect your electrical cord to the power pedestal. The circuit analyzer indicates faults for reverse polarity, open neutral and other wiring issues. Includes integrated surge protection of up to 4,200 Joules.50Amp male (NEMA 14-50P)/50Amp female (NEMA 14-50R). Doesn't protect against sustained high or low voltages.