Amazon.com: Seismic Audio - 18" Raw Subwoofers/Woofers/Speakers - PA DJ Pro Audio Replacement Sub - 750 Watts RMS - 240 oz Magnet - 8 Ohms - 4" Voice Coil : Musical Instruments
Amazon.com: 5 CORE 18" Raw 850W Peak Sub Woofer Cast Steel Basket Driver for Pro Audio PA DJ Cabinets Subwoofer with High Handling Power 500W RMS Extremely Clear and Loud Replacement Speaker