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When a Pokémon with this ability consumes an item or has one removed from it (for example, by Trick, Knock Off, Bug Bite, Fling, or Natural Gift) its Speed is doubled until it switches out. This boost is not a change to the Pokémon's Speed stage, so if a Pokemon used Agility after Unburden activates, it would have four times its original Speed. The Unburden boost cannot be Baton Passed, and losing items after the first does not provide additional boosts. Regaining an item does not remove the boost.