These are very interesting alternatives to the more common spikes and washer isolation footers. The Thixar Silent Feet uses gel pads under each of the four footers to dampen and cut out unwanted vibrations from reaching up to your source unit or preamp. Each set of four will take up to 110lbs. They are designed more specifically for vibration sensitive components like CD players, turntables (within it weight limit) and preamps. The gel side sits facing down the shelf while the non-gel side, is where the feet of your component sits on. These are the slightly cheaper black version.
The set you see here was a former demo set from our contact in Europe. Minor signs of use but nothing major. Original case included. They are made in Germany.