Pokemon Zygarde Box - Rules of Play says:

Encounter multiple Formes of this Legendary Pokémon with the Zygarde Box! Which contains a neverbefore- seen foil promo card featuring Zygarde, 3 Pokémon TCG booster packs to expand your collection, an oversize card featuring Zygarde-EX and a code card for the Pokémon Trading Card Game Online!