MB Quart NA4-400.2 2-Channel 400W Max Marine Powersports Class-D AmplifierBRAND NEW MB QUART NA4 400. 2 Nautic Series 2 Channel Waterproof Marine Powersports Class D Amplifier Key Features: Compatible Vehicle Fitment: Universal Marine Grade Protection IPX Rating: Meets or exceeds IP67 standards for waterproof and dustproof. Potted Internals: The potting material seals the components, insulating them and ensuring better durability, especially in harsh environments where exposure to moisture or water might otherwise cause