ZipSeal

All backpack fabrics used by EXPED are by definition "waterproof" due to their coating and have a water column of at least 1500 mm. The distinction therefore relates primarily to construction and processing:

In "water-resistant" backpacks, water can enter the backpack through the seams and through the zippers.

We define "weatherproof" as backpacks with a water column of at least 3000 mm, which also have water-repellent zippers to the main compartment and seam-taped seams. Although the zippers are very water repellent, water can enter through the zipper during heavy rains.

Our backpacks labeled "waterproof" have a water column of 3000 to 10'000 mm, are also seam sealed or welded, but use water repellent zippers only on exterior compartments, not on the main compartment. The main compartment of these models have a waterproof seal by means of a roll top. In these models, we do not refer to exterior compartments with zippers as "waterproof", but only as "weatherproof". No rule without exception: A 100% waterproof Drysuit zipper is used on the Tempest Duffles.