The Wilson Portable Ball Machine combines state-of-art portability with the performance you expect from Wilson. The first measure of a portable machines its actual portability . The Wilson Machine is lighter (38 lbs.) and more compact than any ball machine with similar features. Plus, it includes a built-in handle and towing wheels to enhance portability. The Wilson Portable Ball Machine also features: Trajectory Control - Variable from groundstroke to lob so you can practice all the shots, including overheads. Speed Control - Adjustable from 10 MPH to 75 MPH. The slowest speeds are useful for younger players. The highest speeds are equivalent to professional-level passing shots. Interval Control - Sets the time between ball throws from one ball every 1-1/2 seconds for rapid volleys to one ball every ten seconds. Spin Control - Adjustable for flat shots, or for varying degrees of topspin or back spin. Built-in Oscillator - Delivers balls either in one position, or randomly across the court so you can practice hitting on the run. Battery Life - Three to four hours per charge. Enough for a serious work out. Ball Capacity - 110 balls. All-in-One Control Panel - All functions are controlled by a single electronic control panel. Includes 3 year parts and labor warranty