The KX-181A is an active 18-inch PA bass-reflex subwoofer with a 1,400 W RMS amplifier, integrated digital signal processor and six selectable presets. It provides a frequency range of 30 to 400 Hz and a maximum SPL of 134 dB. The enclosure uses 18 mm Baltic birch plywood and includes four carrying handles, an M20 attachment thread, temperature-controlled cooling and power linking for up to four units.