The Sinister SDX 2500 Class D Mono Block Subwoofer Amplifier is the most powerful amplifier Wet Sounds has ever built. Employing Class D technology plus the Wet Sounds exclusive MAXED Power Supply, the Sinister SDX 2500 achieves an efficiency rating of over 87% – one of the highest available in a marine amplifier. This means more power, less current drain, less strain on the electrical system, less generated heat. All resulting in more playing time!