The Poke Ball Plus is a device that players can purchase that can only be used in connection with this game. Players can use the Poke Ball Plus as an additional controller when playing this game, and by connecting your game to a Poke Ball Plus, you can even receive the Mythical Pokemon known as Mew via the Mystery Gift feature. On top of this, players can send the Pokemon they catch within the game to the Poke Ball Plus in order to take them on a stroll.
As you walk with one of your Pokemon within the Poke Ball Plus, you will earn both Experience and Items by doing a variety of things. Your Pokemon within the Poke Ball Plus will randomly call out to your trainer through vibration of the device, and if interacted with in time, you will earn more experience. You can even play with your Pokemon in the Poke Ball Plus by holding down the control stick for two seconds in order to initiate Play Mode, earning experience by gently shaking or rotating the device after doing so. Finally, the Poke Ball Plus can connect to Pokemon GO, and you can earn even more experience by doing stuff with it within said game. (You will also earn experience and items simply by walking with your Pokemon while it is in the Poke Ball Plus.)
While you play with your Pokemon within the Poke Ball Plus, you will reach certain milestones depending on the interaction you have with them. When you hit a milestone, you will receive an additional reward of Species Pokemon Candy specific to the Pokemon you have within the Poke Ball Plus. You will earn one of their type of Pokemon Candy for each milestone you meet, receiving it after returning the Pokemon to your game. Sometimes, you may even receive batches of Rare Candy when milestones are met and Pokemon are returned from the Poke Ball Plus.