PolkAudio Powered Subwoofer.
Specs: https://www.cnet.com/products/polk-audio-rm6750/specs/
I am selling the SUBWOOFER ONLY; link is just for spec information
- Stereo Y-Speaker input and output
- Stereo RCA Line-in;
- Volume and Low-Pass Dial-Knobs
- 0-180 degree Phase Switch
- Power Switch