CUSTOMER'S FIRST CHOICE - The NXL series impressive power output is supplemented by its outstanding efficiency, and its durability in harsh conditions makes it a favorite among customers in need of a waterproof amplifier to be the powerhouse of their system. PERFECT MATCH - The NXL Marine Amplifier series is perfect for outdoor enthusiasts looking for a durable, waterproof amplifier with intense power for their marine vehicle's audio system. This series is best used in various rugged and wet environments, such as on trails or at the lake. ULTIMATE PROTECTION - All NXL units have stable and reliable 4-layer PCB layouts, IP67waterproof rating for power sports, has an ultra-compact size for easy installation, and has audio precision quality control verification. UV, Salt and Fog Protection. SMALL AND POWERFUL - The NXL-X850.4D comes in a 4-channel configuration making it great for powering more complicated active setups. Maximum output of 600W x 2CH bridged at 4-Ohms, 200W x 4CH at 4-Ohms, and 300W x 4CH at 2-Ohms. WATERPROOF AMP - DS18 designed the NXL-X850.4D for customers looking for a compact and waterproof amplifier with exceptional power output and prioritizes boosting sound.