The Electro-Voice ETX-15SP Subwoofer features a 15-inch DVX woofer for maximum punch, 1800 W Class-D power amplifier with integrated FIR-Drive DSP, 134 dB peak SPL, DSP preset for true cardioid performance across the full operating bandwidth, combo pole cup (insert and threaded) for use with the ETX Powered Loudspeaker full range models, as well as removable casters.