Amazon.com: 18 Sound 18NLW9601 18" Woofer/80HMS/3600W - Set of 1 : Electronics
18-in next generation high performance subwoofer, specifically designed for high SPL very low frequency applications in either a reflex, bandpass or horn loaded configuration - Walmart.com
Eighteen Sound 15LW1401 - 15" 1,000 Watts AES High Power Woofer