The best way to protect your travel backpacks is to make them inaccessible to thieves.
Travel backpacks are obvious targets for thieves on public transport, in hotels or at airports. Indeed, they are light and easy to transport, and they often contain objects of personal value.
You can use a security strap to lock the zip or use a padlock on the side or back of the bag to make any attempted theft quickly visible. But that's not necessarily practical.
Otherwise there are anti-theft backpacks. Their particularity: Closures and pockets facing the interior!
As a result, any intrusion is impossible without you realizing it.
In addition, these backpacks are also resistant to tearing, cutter or knife blows. They are also waterproof.