Sony SS-WSB101 passive subwoofer, it works great and it is in good shape. This is not a powered subwoofer, it is a passive subwoofer so make sure it will work with your receiver. If you have a RCA output for a subwoofer, it will not work, you need to have an actual subwoofer plus and minus output in order to use it or you can put it at the speaker B outputs! I will have it connected to the garage stereo so you can hear it before buying. The price is $20 firm, not negotiable!