This is the Head Instinct Adaptive Kit. I purchased it new and have never used it. This kit is used for customizing HEAD tennis rackets, especially the INSTINCT series. It includes parts for adjusting the balance and swing weight of the racket. By customizing the racket to better suit your needs, you can expect improved performance. It is compatible with HEAD INSTINCT series rackets. I believe the condition is good, but please refrain from returns. Please make your judgment based on the photos, and understand that this is a used item. Please refrain from purchasing if you are a perfectionist or overly concerned about details.