Its a BASS Boss 600 self contained subwoofer and amp pkg. It actually works great. I do not need 3 cars away bass, just enough to fill the bottom end thats missing. It was a easy install, sounds great. Here is a link to read about it. http://www.amazon.com/Boss-BASS600-Low-Profile-Amplified-Subwoofer/dp/B000OSZA44/ref=sr_1_1?ie=UTF8&s=electronics&qid=1253157447&sr=8-1
