The Sport Ball is a PokéBall you cannot obtain outside of the National Park's Bug Capture Contest. This ball has a 1.5 Capture Rate and is used in order to obtain the Pokémon within the National Park. In Gold, Silver & Crystal, this was called the Park Ball. This item cannot be given to Pokémon to hold. If a Pokémon is captured in this PokéBall and traded to Diamond, Pearl or Platinum, it will revert in those games to an ordinary PokéBall.
CatchValue = ((( 3 * Max HP - 2 * HP ) * (Catch Rate * 1.5 ) / (3 * Max HP) ) * Status Modifier