Boss Audio 1000W 4 Channels Bridgeable Marine Amplifier Features: Fully Marinized Feature a unique rubber door which tightly seals all control panel openings when not in use. It uses inline weatherproof connectors for all input and output connections Tri-Mode Operation Power & Protection LEDs Remote Subwoofer Level Control Input Sensitivity Selector Type: Marine Amplifier Speaker Size: N/A Amplifier Class: Class AB Amplifier Channels: 4 Channels Bridgeable: Yes Built-in Crossover: Yes Crossover Frequency Range: Variable Low Pass Crossover: 40 to 150 Hz