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Ultralight hikers are always looking for the next best thing, and one thing is clear—Challenge Outdoor’s lineup of Ultra fabrics is it. For discerning customers, Ultra’s promise of extreme durability and longevity at a low weight is hard to ignore. But for the average customer, things are getting a bit confusing. As the Ultra product line expands, there are more names to keep track of and choices to make. In this buyer’s guide, we’ll run through what makes Ultra unique and things to remember when making a purchase, plus a detailed explanation of all the fabrics on offer from Challenge Outdoors.
If there’s one thing that sets Ultra fabrics apart from most others, it’s the use of UHMWPE, or ultra-high-molecular-weight polyethylene. UHMWPE is a type of plastic that, by weight, is stronger than steel. Fabrics made with it (like Dyneema, formerly the dominant name in this space) are incredibly strong and abrasion resistant. Every fabric that Challenge Outdoors makes with “Ultra” in the name is made using UHMWPE in some form or another. The company’s other fabrics, like Ecopak and RBC, don’t contain UHMWPE.
For customers, one of the most confusing things about Ultra fabric is the name. “Ultra” is now a trademarked name used by Challenge Outdoors, but the term “Ultra” is also used to market a wide variety of outdoor products from other companies.
As a rule of thumb, most cottage brands that use Ultra in the name (like ULA’s Ultra lineup ) are referring to fabrics from Challenge Outdoors. In the wider world of the outdoor industry, though, you should double check. The Deuter Aircontact Ultra , for example, is not made with Challenge Outdoor fabric, and instead refers to the fact that the Ultra is the lightest pack in Deuter’s Aircontact line. When dealing with a term as ubiquitous as Ultra, it pays to make sure you know what you’re getting. And—although it may seem obvious to some—a white pack or tent fabric does not equal Ultra.
Ultraweave is the most popular fabric made by Challenge, and is considered the strongest pack fabric available for ultralight packs. It’s fully waterproof, and incredibly difficult to tear or abrade in daily use. It’s available in four different weights (100, 200, 400, and 800 denier), but 100 and 200 are most common. A new version, called Ultra X, was released this summer. It now includes a cross-ply layer of UHMWPE strands designed to resist diagonal stretch. Challenge has said that Ultra X is an upgrade to Ultra, and that all production moving forward will be Ultra X. Brands are currently selling gear made with original Ultra, but before long, Ultra X will replace the old fabric across the board.
Best for: Tough, light, and waterproof packs, as long as price isn’t a concern.
Construction: Two-layer laminate fabric consisting of a 66 percent UHMWPE and 33 percent polyester weave with a RUV (a recycled, UV-resistant polyester) film backing. Ultra X adds a UHMWPE crossply layer, as well.
As seen in: Zpacks Arc Haul Ultra
The best way to think of Ecopak is as a 100 percent recycled alternative to X-Pac, a three-layer laminated fabric that’s largely considered the most durable lightweight fabric that’s not made with UHMWPE. Like Ultra, Ecopak is waterproof, though the face fabric is not, so Ecopak can hold some water weight. It’s not as strong or as light as Ultra, but it’s also considerably less expensive—packs made of Ecopak might be $100 or more cheaper than an Ultra model. Plus, if you’re averse to the odd, wrinkled look of Ultra, Ecopak looks sleeker (and offers more color options).
Best for: Super-durable packs without the price tag of Ultra.
Construction: Woven polyester face with PFC-free DWR, a polyester cross-ply, and a 70-denier ripstop poly backing. A lighter version (that’s still heavier than Ultraweave) called EPLX, has an RUV film backing rather than polyester.
As seen in: Wamark EMBR
Like Ecopak, Ultragrid is essentially a recycled version of a fabric that most ultralighters are already familiar with: nylon grid fabric. There’s nothing that truly sets Ultragrid apart from other nylon grids, apart from the recycled nylon content. Unlike Ecopak and Ultra, Ultragrid is water-resistant rather than waterproof. It’s also worth mentioning that Ecopak is 100 percent recycled, while Ultragrid is not. That’s down to the UHMWPE grid, which is difficult to recycle.
Best for: Affordable ultralight packs
Construction: 210-denier recycled ripstop nylon with an Ultra grid, PFC-free DWR face coating and a polyurethane inner coating
As seen in: Mountain Laurel Designs Prophet
RBC is essentially the woven polyester material that forms the basis of Ecopak. By itself, it’s not as durable as Ecopak, but it’s even cheaper—about half the price per yard. It doesn’t contain any of the fancy UHMWPE or cross-ply lamination of the more expensive fabrics, and isn’t widely available. Few brands use it as the primary fabric in their gear, though packs made out of Ecopak sometimes include RBC on small areas like shoulder straps or as an interior liner.
Best for: Travel packs or accessories
Construction: Single-ply polyester with a DWR-finish
As seen in: Organic Climbing R.B.C. Chalk Bag
The TX line is basically a cross between Ultra and Ecopak. It takes the the Ultraweave fabric and sandwiches it to the polyester backing fabric of Ecopak. As with Ultra X, an ultra cross-ply between these layers adds extra resistance to stretch. Combined, it’s quite a bit heavier than standard Ultraweave but should be even longer-lasting and bulletproof. The face fabric is the same, but thanks to the stronger backing material, it’s less likely to delaminate. One concern with standard Ultra is that the thin film backing can come loose with sustained use, though its unclear how common this is or how it affects the overall performance of the fabric. Like Ultra, TX is available in 100, 200, 400, and 800 denier versions. It’s not, however, very widely available, and it’s unclear if more brands plan to use it in the future.
Best for: Bombproof packs with a weight penalty
Construction: Ultraweave face fabric, Ultra cross-ply, and a ripstop polyester backing
As seen in: Not much, outside of tiny cottage brands that do custom work, like KS Ultralight
If you couldn’t guess by the name, Ultrastretch adds UHMWPE to a blend of stretch fabric, making a durable option for pack pockets (if you’re wondering how a fabric with a material as strong as UHMWPE can stretch, manufacturers can adjust yarn tension in a weave, allowing some strands to stretch before others are affected). It’s not the only stretch fabric with UHMWPE on the market, but it is a popular option, especially on packs that use Ultra or Ecopak for the main pack body.
Best for: Stretchy pack pockets
Construction: Nylon, lycra, and Ultra blend
As seen in: Outdoor Vitals Skyline
UltraTNT is the black sheep of the Ultra lineup—a fabric designed for use in shelters rather than packs. As a tent fabric, it occupies a unique niche. It’s not light enough to rival Dyneema shelters, and more expensive than basic options like silnylon or silpoly . However, it is very strong, lighter than every option but Dyneema, and has a three-way grid that makes it very stable under tension. It’s also brand new, and only available from a few companies. In the future, expect more adoption, especially as a strong and light four-season shelter fabric.
Best for: Zero stretch tarps and tents at a better price (but higher weight) than Dyneema.
Construction: An Ultra grid sandwiched between two layers of PET film.
As seen in: Tarptent Scarp 1 Ultra
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