The Aircontact Core 60+10 is the expandable workhorse of the big-pack tier, and its best features are the practical ones rivals skip. The collar stretches capacity from 60 to a genuine 70 liters, which means one pack covers everything from a weekend to a gear-heavy week without buying twice. The full-length J-zip opens the pack like a duffel, giving easier access to the bottom of the load than any top-loading Osprey — a small thing on paper that you appreciate every single evening in camp. And the Y-frame with mobile hip fins moves a heavy load well, keeping the weight coupled to your hips as you walk. At $260-300 it undercuts the Osprey Atmos AG 65 and Gregory Baltoro 65 by $60-100 while carrying nearly as much. The catch is that it matches those premium haulers' weight — 4 pounds 12 ounces empty — without quite matching their signature strengths: the Atmos ventilates dramatically better through its suspended mesh back, and the Baltoro's harness handles the very heaviest loads with more composure. That leaves the Deuter as a strong, sensibly priced second choice rather than a category winner. If the J-zip access or expandable capacity fits how you actually camp, it is a thoroughly justified pick.
Collar expands capacity from 60 to 70 liters for trips of any length
Full-length J-zip gives the easiest bottom-of-pack access in its field
Y-frame and mobile hip fins carry heavy loads well for $60-100 less than premium rivals
At 4 lb 12 oz it matches premium haulers' weight without matching their strengths
Ventilation trails the Atmos AG's suspended mesh back