JBL JRX118SP Self-Powered Single 18-inch 350 Watt Subwoofer, Dual Inputs, Built in crossover The rugged enclosure is constructed from 19 mm (3/4-Inch) MDF (Medium Density Fiberboard) using advanced adhesives and mechanical fastener technology for durability and improved low-frequency performance Built-in 500 watt (peak), 300 watt (continuous) amplifier, Controls, connectors, and indicators are clearly labeled with large, high-contrast graphics for easy operation in poorly lit environments Integral, preset limiter prevents clipping distortion Required AC Mains: 50/60 Hz (North American units are 60 Hz only), 120 and 230-240 VAC (10%) units are available A speaker-level, 1/4-Inch TS phone jack is provided