The heavily weighted base keeps the punching bag firmly in place. The base can be filled with sand or water. The speedball allows the boxer to practice dodging, punching speed, footwork, and hand-eye coordination. The ball recovers quickly from the punch, requiring a quick response from the boxer. Also suitable for practising other martial arts, such as karate, MMA and Thai boxing. The speedball is mounted at the appropriate stroke height according to the length of the boxer.