Expansion and contraction to fit your load. Expandable gusset is very thoughtfully designed; it works without you having to think about it.
Surprising amount of space for how small this thing can look on the body. Mirrorless cameras with small/pancake lenses will likely fit, for example.
Totally customizable and removable inner organization. Can all be removed and makes a great daily carry bag (or leave some in and customize for how you carry).
The Duffelpack from Peak Design expands from 45L to 65L (a little too large for carry-on on most airlines), has backpack straps that hide away, is made of weatherproof material and is a durable and organized companion for LOTS of different kinds of adventures. view bag