Unlike other Battle Gear, the Bakugan are attached to them, making it compatible to any Bakugan. When a Bakugan is placed on an closed BMA it opens up. Also, they have an attribute that must match the Bakugan using the BMA. A maximum of 2 BMAs can be used in your force (Trap/BMA, Battle Gear/BMA, Mechtogan/BMA, Mechtogan Titan/BMA or BMA/BMA). They each come with a Reference Card listing what type of Gate Card (Copper, Silver and/or Gold) they can be used on and it's special abilities.