With the push of just one button, the Player Model (Patent-Pending) simulates a player on the other side of the net. Just push either the Beginner, Intermediate or Advanced button, and the Player model automatically picks an appropriate speed and spin, then changes both the side-to-side position and the depth of shots just like you were playing someone of that ability.The side-to-side position and depth of each shot are not simply changed in a random or sweeping motion, but are computer programmed to simulate the shot patterns of real players. For instance, beginning players will see more shots toward the middle of the court and more variation in depth of shots than will advanced players. And you are not stuck with only the standard settings, you can customize the settings by adding or subtracting more speed, spin, or elevation as you like.This model is battery powered.Warranty. Tennis Tutor ball machines are backed by a three-year warranty ( 2-YEARS of Factory Warranty Remaining) covering both parts and labor. Extended warranties available.Includes smart charger and RemoteBall capacity: 150 Balls Trajectories: Groundstroke to Lob Ball ejection speed: 10-85 MPH Ball feed rate: 1.5 to 12 seconds Oscillator: Built-in Playing Time w/heavy duty battery: 4 to 6 hours typical Recharge Time: 12 hours, typical Dimensions hopper closed: 20"H x 19.5"L x 20"W