Thank you for viewing. This is a set of 7 Tiglon D-REN PRO spacers. They can be used to prevent wobbling of insulators for audio equipment, or used individually, making them versatile and useful. The size is 70mm in diameter and 3mm thick, with a structure that sandwiches a pure magnesium sheet with special rubber, and the product boasts high vibration processing capabilities. My personal impression after actually using them is that, as the manufacturer describes, the playback sound changed dynamically and vibrantly. This is an odd number of 7 pieces, but thank you for your consideration!