Spectrum Pieces (スペクトラムピース (formatted as Ｓｐピース exclusively in card text) Supekutoramu Pīsu) are the pieces of the Spectrum Wheel. Each Spectrum Wheel has seven Spectrum Pieces, all of which are missing from the Wheels at the start of the Duel. Spectrum Pieces can be added and removed from the Wheels via card effects. When a Wheel has seven Spectrum Pieces, the player can perform a Spectrum Summon. Some card effects can also be specific with the color of the Spectrum Piece affected, either for addition/removal or as a requirement to even activate the effect.
In Action Duels, Spectrum Pieces are scattered throughout the Action Field, and effects that add Spectrum Pieces to the Wheel cannot activate, so the Duelist must actively hunt the Spectrum Pieces down in order to Spectrum Summon during an Action Duel.
Like the Spectrum Wheel, Spectrum Pieces are completely separate from the field and are not cards, so effects that target cards will not affect them.