Track Audio's Solid Feet (formerly Coupled Isolation Feet) are big, heavy solid, steel spikes. They have a >150Lb rating each. A set of four holds over 630 lbs. They make a huge difference under speakers, racks, amp-stands, etc. They come standard with a set of Track's stainless cone cups. Solid Feet are the most massive adjustable after-market spikes we've ever seen. Weighing in at just under a pound each, these are not just big, they're cleverly engineered as well. Solid Feet are a stunning upgrade for any component.