What is the difference between airbag-integrated and airbag-compatible packs?

Airbag-integrated packs have the airbag system built permanently into the pack—you cannot remove it. Airbag-compatible packs have a dedicated sleeve that accepts a removable airbag module (sold separately). Compatible packs offer flexibility: you can use the same airbag module in different pack sizes, remove it to save weight when you do not need it, or upgrade the module later. Integrated packs are simpler and often slightly lighter for the same airbag capacity, but you are locked into that specific pack and airbag combination.