Walker HD links are a small wooden box, maybe 2" X 1" X 1/2". They have two small silver wires with silver spades soldered on, and they go "across" the plus and minus lugs on the speakers, where amp connection is made. They retail for $300.00, and require break in before you can hear what they are capable of. In my system, everything improved, top end resolution, smoothness, extension and impact in the bass and imaging. Hard to believe this small device can make so much difference for so little money. I suspect that results will vary, depending on the equipment associated and the type of speaker. I can only speak from experience with my system.