Accelerator 3...Improve Your Short Game! Accelerator 3 enhances your home practice putting with the same indoor artificial golf putting greens as the original Accelerator and Accelerator II. The Accelerator 3 features the only continuous gravity ball return of its kind. Accelerator 3 Putting Trainers feature: Portable indoor golf practice putting green made of artificial synthetic turf mat Uneven turf green closely resembles the putt on a true golf course May be used for 3", 5", or 7" long putts Special ball track is designed to adjust to the specific putt distance you are practicing Continuous gravity ball return May be used at home, office or other venues to improve your golf putting game Practice Your Putting With The Accelerator 3!