Savotta Rolltop Stuffsack 80L, 500D

Whereas your ”common pack sacks” tend to be made from nice, lightweight fabrics these are quite the opposite. First of all these are not intended for use within backpacks/bags, but as stand-alone crude transport bags. The strong 500D Cordura endures rough use, including transport of abrasive and bulky gear and that sort of real-life negligent handling our gear sometimes have to face. You could describe these as a very crude, low-tech option for actual duffel bags.