From Bulbapedia, the community-driven Pokémon encyclopedia.
A Ball Capsule (Japanese: ボールカプセル Ball Capsule) is a special item introduced in Generation IV that can be attached to a Pokémon's Poké Ball to add special effects when the Pokémon is sent out in a battle.
In the games
Ball Capsules may be accessed from the player's own PC. There are twelve spaces for them to be saved on, and their appearance can be altered by adding Seals to their exteriors, which are used to create a variety of special effects. Most Seals can be purchased in the Sunyshore Market at Sunyshore City. A total of eight Seals can be attached to a Ball Capsule at one time.
If a Pokémon whose Poké Ball has a Ball Capsule is to be released or stored in the Pokémon Storage System, the Ball Capsule must be removed. Likewise, when a Pokémon is traded, the Ball Capsule will automatically be removed.
NPC Trainers in Pokémon Platinum use Ball Capsules, notable examples include the Sunyshore Gym Leader Volkner and the Elite Four member Flint, who use Ball Capsules on the Poké Balls of their Electivire and Magmortar, respectively.
Ball Capsules and Seals were removed in Generation V.
In the anime
demonstrating how to use a Ball Capsule in the anime
When Pokémon Coordinators debut in Pokémon Contests, they get a Contest Pass, a Ball Capsule, and a few Seals. These were first shown in Mounting a Coordinator Assault!. While Contests seem to be their main use in the anime, they cannot be used in Contests in the games.
In the manga
In the Pokémon Adventures manga
In Knowledge of the Unown I, Platinum receives a Ball Capsule and some Seals as thanks for giving the Pokémon News Press information on Unown.
In other languages