>>39302159Looks like Serebii answered that question for me
>As a special bonus for purchasing the Dual Pack SteelBook® Edition, Trainers will receive two codes (one per game) that will reward them with special items known as Dynamax Crystals. By using the Dynamax Crystals in the Wild Area, Trainers will be able to face Dynamax Larvitar and Dynamax Jangmo-o, Pokémon that are normally encountered later in the game, in special Max Raid Battles. Larvitar won’t appear in Pokémon Sword and Jangmo-o won’t appear in Pokémon Shield during normal gameplay, but players will be able to catch them in either version by using these Dynamax Crystals.