What's the difference between airbag-compatible and integrated airbag packs?

Airbag-compatible packs have a sleeve or compartment that accepts a removable airbag module (like the Mammut Removable Airbag or Ortovox Avabag), which you purchase separately. You can swap the module between compatible packs and choose whether to carry the airbag on any given day. Integrated airbag packs have the airbag system built into the pack permanently—they're simpler to use (no module to transfer) and often have better trigger ergonomics, but you can't remove the airbag to save weight, and if the pack wears out, you replace the entire system.