I bought this for my nephew, who is in his first year of baseball (late starter). After going 9 games without a hit the machine arrived and he used it everyday for a week.... sometimes hitting more than 500 balls in a day. After a week of constant use he went 3 for 4 in his next came. The product changed helped his eye, his swing, and more importantly gave him a ton of confidence. He now only uses the GroBat and he is continuing to improve. He now hits the ball longer and harder.... can't say enough good about the personal pitcher.