FIRST DEFENSE 250-series Marine Surge Protector offers the best portable surge protection available for your boats 30 Amp, 120-Volt electrical system. The 250-series Marine Surge Protector features All Mode Protection, protecting Line to Neutral, Line to Ground and Neutral to Ground from power surges originating from your shore power connection. While these surges typically do not cause instantaneous damage, they cause cumulative damage as these extremely fast, low power surges bombard sensitive, micro-processor based equipment on-board your boat. Our 250-series Marine Surge Protector comes standard with EMI/RFI filtering to protect against transient electrical surges. We believe our 250-series marine surge protector is the best in the industry with 120,000 Amp Total Peak Surge Current protection for those nearby lightning strikes which can enter your boat's electrical system from its shore power connection. We lead the industry in let-through voltage performance. Our 250-series marine surge protectors offer circuitry encapsulation to protect the SPD's circuits from weather and vibration. In addition, while others offer a weather resistant box, we use NEMA 4X liquid tight enclosures, the ultimate for weather resistance to extend the life of your surge protector.