Unlike the Sword and Shield double pack, it appears the Brilliant Diamond and Shining Pearl double pack won’t feature a special steel case.
Brilliant Diamond and Shining Pearl are re-imaginings of the original Pokemon Diamond and Pearl released on Nintendo DS in 2007. The Pokemon Company first announced the games in a February Pokemon Direct, though shared few details on what new features we can expect from the remakes.
The recent announcement is no different, as TPC only shared the release dates and nothing further.
So far, we know the Brilliant Diamond and Shining Pearl Pokedex includes the entire Sinnoh Pokedex, as the originals did, though it’s not clear if we’ll see additional ‘mon such as we did in Omega Ruby and Alpha Sapphire.
TPC will likely share more soon, as they usually host a Pokemon Direct coinciding with E3.