The Choice Scarf (Japanese: こだわりスカーフFixation Scarf) is a type of held item introduced in Generation IV. It has two counterparts that boost different stats: Choice Band and Choice Specs.
In Generation VII, if a Pokémon holding a Choice Scarf uses a move other than the one it's locked into (such as through Embargo or Dancer), the move will fail and no PP will be consumed.