The Expedition Rucksack Liners from Exped are pack shaped versions of
the folding Dry Bags. In contrast to packsacks with round bottoms,
these waterproof liners are better shaped to perfectly fit a backpack
and completely fill the space. Comes with a fast access roll-n-fold
closure. Made from a lightweight, durable PU-coated 70D Taffeta nylon
with a water column of 10,000 mm.