Surge Protection: Absorbs high-voltage spikes and surges to protect your RV electrical equipment from damage. Circuit Analyzer: You can judge the circuit fault by the indicator light, which protects you from poor and unsafe electrical conditions, such as open ground, open neutral, reverse polarity, reverse ground, and overheating. Specification: Rated 30A 125V 3,750W 2,100 joules surge protection with 22,500 max spike amp. Instantaneous response with less than 1 ns response time. Flame Retardant Material: RVGUARD surge protector made from flame retardant material has a huge operating temperature range from -40℉ to 140℉. ETL Listed: Our entire product is ETL/cETL certified, providing a higher level of safety for your RV compared to other brands that only have UL certification for their plugs or cables..