The Sports Tutor Tennis Tutor Player Plus is truly portable, measuring only 12 inches tall when the ball hopper is folded down for transport; with the towing handle extended, it tows just like luggage. When you get to the court, the ball hopper opens in seconds to hold 150 balls, which is more than two standard pick-up baskets full of balls. Tennis Tutor comes standard with a built-in heavy duty rechargeable battery that can deliver up to six hours of playing time, so there’s little need for extra batteries. But if you do want more battery life there is an optional External Battery Pack that can be installed if ordered at time of purchase. Tennis Tutor has a built-in battery charge indicator, and it even politely beeps when there is only one-half hour of battery charge left. And of course, Tennis Tutor comes complete with a plug-in charging unit that fully charges the battery overnight.Player Mode - simulates a real player. Automatically picks an appropriate speed and spin, then changes both the side-to-side position and depth of shots, which are computer programmed to simulate the shot patterns of real players at the Beginner – Intermediate – Advanced levels.2-line oscillator feature – Shoots balls to two preset positions. This allows a player to practice alternating forehand and backhand shots and helps an instructor work with two lines of students in a group lesson. There are two 2-line settings: Narrow & Wide.Features: Ball Speed: Up to 85 MPH.Ball Feed: Adjustable from one ball every 1-1/2 seconds to every 10 seconds.Electronic Elevation Control: Ball trajectory is electronically adjustable from groundstroke to lob.Built-in Oscillator: Delivers shots randomly across the court for hitting on the run.Rechargeable Battery: Built-in battery provides up to six hours of playing time per charge. Even more playing time is available with an optional External Battery Pack.Low Battery Charge Indicator: Politely beeps when there is about one-half hour of playing time left.Smart Battery Charger: Fully charges the battery overnight and shuts off automatically to prevent over-charging. An optional smart/fast charger can charge the battery in lessthan six hours.Start-up Time Delay: Allows the player time to get to the other side of the net before balls begin shooting.Fold-out Towing Handle: Tows like luggage on built-in caster wheelsPlus Features: Includes Topspin and Underspin: A single dial controls the amount of topspin or underspin.A bar graph display shows the elevation setting so you can set it to your favorite spot before firing any balls.Specifications:Ball capacity:150 BallsOscillator: Built-inBattery Type: Lead-acid, solid, sealedPlaying Time w/heavy duty battery: 4 to 6 hours typicalRecharge Time: 12 hours, typicalDimensions (hopper closed): 12″H x 19.5″L x 20″WWeight (includes 12 lbs Heavy Duty battery): 42 poundsMachine Options (Must be ordered at time of purchase)AC Power: All Tennis Tutor models can be ordered with AC power instead of battery...