Amazon.com: DS18 PRO-BX21N.1 Car Subwoofer Audio Speaker - 21" in Neodymium Magnet, 6" Voice Coil, 1 Ohm Impedance, 3000W Rms Power, 6000W Max Power - Reinforced Paper Cone for Outstanding Performance : Electronics
STLF-1890 | 18" Raw Woofer Speaker, 400 Watts Pro Audio PA DJ Replacem – Sound Town
SKP PRO AUDIO TITANX-18600 18" WOOFERS LOW SOUND, Program Power 1200W, Nominal Impedance 8 Ohm, Professional Subwoofers and Deep Bass and Mid-bass - Walmart.com
Lanzar Maxp124d Max Pro Compact 15 Inch Round 2000 Watt Powerful Performance Dual 4 Ohm Vehicle Truck Car Subwoofer Audio System (single Subwoofer) : Target