The HEAD Adaptive Tuning Kit also you to customize your Graphene Touch Speed Adaptive tennis racquets to your preference. You can choose between the more open 16x16 string pattern if you're looking for massive spin, or you can take a more tradtitional approach and keep the 16x19 grommets in. Not only can you select the string pattern, but you can select between lightweight and heavy grommets to help increase the stability of the racquet. The kit also comes with handle spacers that allow you to extend the racquet in 5mm increments (5mm, 10mm, or 15mm).