The new ST-Z Driver further deploys Mizuno's new Forged SAT2041 Beta Ti Face & complex carbon construction to provide the player with potent ball speeds & a dense, satisfying feeling at the point of impact. Working from feedback from the previous year, improvements have been made to the sound produced off the face. Mizuno's engineers have spent a whole year fine-tuning the sound to a more muted & powerful tone. The Mizuno ST-Z Driver is a balanced toe/heel carbon composite construction with deep central back weighting to deliver a spin efficient, straight-line bomber that is ultra-stable with low spin performance.