This.Two different kinds of woofers.
https://ssl.perfora.net/www.ficaraudio.com/sess/utn154c7025cc4d273/shopdata/0050_Speakers/0020_BL/product_overview.shopscriptbl12
Audioque: Heavy Duty: HDC3
249
DC Audio - Woofers
level 4
Dreadnaut subwoofer by MMATS - eBay (item 140442065069 end time Sep-16-10 20:35:21 PDT)
MMATS Juggernaut 12" Subwoofer, 1400 Wrms of power - eBay (item 160469912263 end time Aug-24-10 15:14:52 PDT)