Definitive Technology Pro Sub 600 powered active subwoofer. The sub is fully functional and in great shape, 8" woofer in front and a passive woofer at the bottom that makes the bass very smooth. It goes loud but don't expect much from an 8" woofer. Great for a sound bar or a home theater system. Dimensions: 10.25" Wide, 13" High and 15" Deep. I will have it hooked up to the garage stereo so you can hear it before buying! The price is $80 firm, not negotiable!