M400/4 4 Ch. Class D Full-Range Marine Amplifier, 400W; M Series marine amplifiers feature hyper-efficient NexDTM Class D technology to deliver audiophile-grade performance and outstanding efficiency from within an incredibly compact package. Advanced thermal management systems and a full complement of studio-grade signal processing features are standard, and an HD-RLC can be added to all models for remote level control. Available in a wide range of configurations to suit any system design.