RCF L15P540, Woofer 15", 500 Watt RMS @ 8 Ohm | MUSIC STORE professional
dB Technologies ARENA SW 15 15" Subwoofer, 500 Watt RMS | MUSIC STORE professional
Amazon.com: Pyle 8 Inch Car PA Woofer - 500 Watt High Powered Car Audio Sound Component Speaker System w/ 1.5" Kapton Voice Coil, 55-6 kHz Frequency, 89.2 dB, 8 Ohm, 40 oz Magnet - PylePro PPA8 , Black : Electronics
Massive Audio MMA Series 12-Inch 500-Watt-RMS Dual 4-Ohm Subwoofer in the Mobile Audio department at Lowes.com