The 3-Ball ServeMaster acts as your “racket” for learning and training. This tennis training tool is designed for adult players of all levels and larger kids who are more accomplished and use a full sized racket. It lets players FEEL the “drag” of the weighted end therefore creating a better “whip like” feel to the serve. You can carry ServeMaster in your bag, use it on or away from the court, practice in your backyard or even on the beach! SM is also great for ground-stroke and overhead work for all players, warm-up, injury prevention and rehabilitation.