Pokémon Center Elite Trainer Boxes are the exclusive version of each set's ETB, sold first through the official Pokémon Center. They hold 11 booster packs instead of the standard nine, plus an extra full-art promo stamped with the Pokémon Center logo, sleeves, Energy cards and a player's guide. They are harder to find than the standard box once the first run sells through, which is why many collectors keep them sealed. See the standard versions in Elite Trainer Boxes.