Bakugan Extension Packs are Extension Packs like Mechtogan Extension Packs. They consist of two BakuMutants, one BakuNano and two Core Bakugan. The BakuMutants are always Mutant Taylean and Mercury Dragonoid, and the BakuNano is always Slingpike.
In Arc 2 of Mechtanium Surge, the Extension Packs contain two BakuFusion Bakugan, one BakuMine Bakugan, and one Baku Sky Raider, 4 Metal Gate Cards, and 4 Ability Cards.
Also, in Arc 2 of Mechtanium Surge, some of the Extension Packs are labeled as "Platinum" packs; which are the same as the regular Arc 2 Extension Packs, but the BakuFusions are both of a different attribute rather than two of the same and in each pack - a regular Bakugan is submitted for one of the BakuGold variation Bakugan.
Later Arc 2 packs include two BakuMutants in place of the BakuFusions.
Description (Arc 2)
Dominate in battle with the fiercest collection of Bakugan warriors. Explode into action with the powerful BakuMine, and connect your BakuFusion to form unique 2-in-1 monsters. The Bakugan Extension Pack also comes with 1 Baku Sky Raider to soar into battle!