Subject is smaller packs that CAN go solo but mostly ride piggy back on a primary pack. I use the KIFARU E&E (1,000 Cu. In.) for a survival/assault pack. It can be removed or re-attached to the Primary pack in about (3) three seconds. https://store.kifaru.net/escape-and-...iters-p56.aspx
My primary is a KELTY "Falcon 4000" (NOT for Hunting)
I have a Tactical Tailor chest'rig that works better when it is very hot weather.
Your thoughts.....what do you choose.........?