Amazon.com: Sound Barrier SBNC18 2000 Watts Raw 18" Sub woofer Speaker Component Driver with 4 inch Voice Coil and Cast Aluminum Basket Pro Audio PA Cabinets - High Handling Power Heavy Duty :
Blastking BLAST18PRO 18" 1800 Watts Professional Low Frequency Transdu – Blastking USA
Amazon.com: SOUND TOWN 18" RAW WOOFER SPEAKER, 400 WATTS PRO AUDIO PA DJ REPLACEMENT SUBWOOFER LOW FREQUENCY DRIVER (STLF-1890) : Musical Instruments