SIMPLE TO OPERATE - Only two buttons. EASY TO TRANSPORT - Compact design weighs only 23 pounds. Built-in carrying handle. BALL THROWS - 20 MPH, 35MPH, 45 MPH. >> BALL FEED INTERVAL - Time between shots automatically adjusts with speed setting. TOPSPIN - Shoots all balls with TOPSPIN so it is for INTERMEDIATE and ADVANCED players. It is not for Beginners. RANDOM OSCILLATOR - delivers shots randomly across the court for hitting on the run. INTERNAL RECHARGEABLE BATTERY – Built-in battery provides up to two hours of playing time per charge. Includes Smart Battery Charger that fully charges the battery overnight and shuts off automatically to prevent overcharging. THREE YEAR WARRANTY - Check this against no warranty for many offshore brands. We can offer this long warranty because we are MADE IN THE U.S.A. >> SERVICE - We are here for you at our factory in Burbank, CA. If you need advice, parts, accessories or service just call us toll free from the U.S.A. SHOT SELECTION - For groundstroke and volley practice. BALL CAPACITY - 70. One standard pick-up basket full of balls. SEE CHART BELOW for more Sports Tutor tennis ball machines, including eCannon without oscillator ($659). Tennis Ball Machine. The eCannon is for groundstroke and volley practice for intermediate and advanced players. It shoots all balls with topspin (like all one-wheel tennis machines), so it is not for beginners.