Brand new in box, never used! Two sets of four Acoustic Revive RIQ-5010 high end audio tuning feet (Insulators). Pure smoky quartz and pure quartz don’t generate their own tone, and they improve the sound quality. Additionally, reproducing sound becomes livelier. You will be surprised that the sound of the instruments and human voice have changed incredibly livelier, and extremely vividly. If you place the RIQ-5010 on the top plate of your equipment or near the input/output terminals, you can get the effects of improving sound. There are some theories why the quartz improves sound. Some say that the pure quartz absorbs an electromagnetic wave, some another say that the pure quartz controlls vibration, or that the pure quartz radiate far infrared light. Anyway pure quartz have effects of improving sound that are never gained from the other materials. RIQ-5010 improves sound quality extremely mellifluously, smoothly, lively and warmly. Additionally, the sound is well-modulated, and the rise time and decay time are both quickly, these two opposite values can be compatible. Note: Because of using pure quartz, crystal structures or impurities are shown inside of RIQ-5010. Please accept this, it is common characteristic of pure quartz. Retail price is 780 euro for the set of four, now for 579 euro for one set only. The original boxes and manuals are included. Check our other listings for more interesting items. Free shipping worldwide!