SealLine

A dry bag is one of the few pieces of outdoor equipment where the failure is total. A jacket that leaks makes you damp. A bag that leaks ends the trip, or the sleeping bag, or the camera. SealLine has been making that argument since 1986, and the thing worth writing about is what its product pages refuse to say.

The brand is one of the in-house names at Cascade Designs, Inc. of Seattle, the same privately held company behind Therm-a-Rest and Platypus — three pages here, one owner, stated plainly so nobody counts them as three votes. Cascade’s timeline puts the founding moment in engineering terms: in 1986, “keeping important gear dry in wet environments becomes easy with the introduction of a double-stiffener closure for SealLine® dry bags, creating the most waterproof roll-down closure on the market.” That last clause is the company’s claim about its own product, from 1986, and it is quoted here as the company’s rather than adopted as this page’s.

Welded, not sewn — and no number attached

The Discovery Dry Bag is the plain statement of what the brand does. The fabric is PVC-free 300D 18 oz polyurethane-coated polyester. The seams are fully welded. The sizes run 5, 10, 20 and 30 liters, weighing 6.2 oz (175 g), 9.7 oz (275 g), 13.8 oz (390 g) and 1 lb 1 oz (500 g). The tech specs say “Made in USA of US and Imported Materials.”

Welding matters because a sewn seam is a line of holes that a coating is asked to seal. Welded seams are a single fused material with no perforations to manage, which is why the technique dominates serious waterproof soft goods.

Now the restraint. The page calls the bags “fully waterproof” and does not attach a submersion rating, an IP figure, or a depth. It does not claim the bag survives being held under. For a category where “100% waterproof” is printed on products that fail in a rain shower, an absent number is a more trustworthy signal than a confident one — and it is the correct signal, because a roll-top closure’s performance is a function of how many times the user rolled it, not of a factory test.

Where they fall down

No published waterproof standard, for anyone who needs one. The restraint above is honest, and it is also a gap. A buyer specifying bags for a boat, a rescue cache or an insured camera kit has no rating to write on a purchase order. “Fully waterproof” is a description, not a specification.

The closure is the user’s job. Three or four folds and a firm clip is the whole waterproofing system. A bag rolled twice in a hurry is not the product the factory tested, and no amount of welding compensates.

“Made in USA of US and Imported Materials” is per model. Cascade describes manufacturing and distribution hubs in Reno, Nevada and Midleton, Ireland. That is a real footprint; it is not a blanket claim across the SealLine catalog, and origin should be read off the model page for the bag in hand.

Coated fabrics have a service life. Polyurethane coatings age, abrade and eventually delaminate. A ten-year-old dry bag that looks fine is a dry bag with an unknown coating, and there is no field test for that short of trusting it with something you cannot replace.

The house’s public recall record sits with a sibling brand. In February 2024 Cascade Designs recalled about 60,655 MSR camping cooking pots over handles detaching, following 22 reports and two burn injuries. No SealLine product is in that recall. It is here because the recalling firm is this brand’s parent.

Where SealLine fits

Paddling and anything that can capsize. The founding use case, and still the one the construction is aimed at.

Boats, tenders and deck storage. Where spray is constant rather than occasional.

Overland and expedition packing. Dust and mud are the same problem as water for anything with a zipper or a lens.

Not for: a rated waterproof case with a gasket and a latch — that is Pelican or Nanuk territory, and a different promise entirely. Not for anyone who wants a depth rating printed on the product.

Why we rate them

They tell you the construction, not just the outcome. Welded seams and a named fabric weight are checkable; “waterproof” alone is not.

They left the number off. In this category, that is discipline rather than omission — a roll-top’s seal depends on the person closing it.

The house is Seattle, private, and consistent. Same owner as the pad brand and the water brand, same habit of publishing fabric, weight and a qualified origin line on the product page.

When the gear has to arrive dry and the water gets a vote, we reach for SealLine.