osprey airframe backpack through luggage handle opening in the back panel Osprey Packs Nebula 34L Backpack

They must also be large enough for the line to move through them without difficulty whilst also being strong enough to endure the abrasion caused by the moving line

You can also keep the empty bladder in your freezer to limit bacteria growth during storage

In default 35L configuration, it meets most international carry-on standards, but it also folds down into a 35L daypack, perfect for urban escapes, and expands to haul 45 liters of gear comfortably when needed

It takes up more room than other picks on this list, so be aware of that when you're packing

It delivers top performance in comfort for carrying large loads and generous space for all your gear with several compartments

Taking multi-use to the next level