Outdoor Research Helium UL Review: Ultralight Yet Versatile
Updated:
May 04, 2026The Outdoor Research Helium UL ($225) is an ultralight shell that sits somewhere between a windbreaker, an emergency blanket, and a true rain jacket. It offers impressive weather resistance for its weight, and its appeal stems mostly from the ability to pack down small enough to live in a pack, suitcase, or even a running vest pocket. The latest version, which features a printed lining, is also impressively comfortable and good-looking. Breathability and features are sacrificed in the name of shaving grams, but for just-in-case protection, the Helium UL fills a useful niche.
Weather Protection
Comfort
Breathability
Weight & Packability
Durability
Sustainability
Waterproofing
2.75-layer Dermizax
Weight
5.7 oz.
Fabric
15D nylon
Vents
None
Packable
Yes (pocket)
Pros
Cons
Outdoor Research Helium UL
For this season's top shells, see our guide to the Best Rain Jackets.
For a sub-6-ounce rain shell, the Outdoor Research Helium UL’s weather protection is legitimately impressive. It uses a 2.75-layer Dermizax membrane with full seam sealing and a thin 15-denier shell. Outdoor Research gives it a 20,000mm waterproof rating, which is much more protective than the minimally protective ultralight models of yore. (Fellow modern featherweights, the Montbell Versalite and the Rab Downpour Light, are also rated to 20,000mm.) If the “2.75-layer” jargon gives you pause, just think of it as a waypoint between the burliness of a full 3-layer membrane (with fabric liner) and the lightness of a 2.5-layer construction (with laminate backer). The Helium UL features a 3D-printed membrane liner that is as lightweight as a 2.5-layer design but offers better moisture-wicking and a next-to-skin feel.
In practice, the Helium UL’s build translates to reliable protection in steady precipitation, at least for shorter efforts. Throughout the fall and winter in my hometown of Leavenworth, Washington, I’ve worn this jacket in pouring rain on cold-weather runs in the 40s and stayed dry from external moisture. (Where it falters isn’t in keeping rain out, but in managing moisture inside the jacket; more on that below.) I wouldn’t want to rely solely on this shell in an all-day deluge while backpacking, but the fact that it’ll prevent you from turning for home if a squall passes through is very impressive considering its barely-there weight. As an emergency shell or one you leave permanently in your day pack or running vest, the Outdoor Research Helium UL does exactly what it’s supposed to.
The Helium UL’s substantial improvement in comfort over the prior generation proved to be the biggest surprise in this test. The 2.75-layer construction uses a 3D-printed liner that feels noticeably better against the skin than the plasticky 2.5-layer interiors of past versions of this shell. The material’s feel isn’t necessarily luxurious, but we had zero complaints even when worn over just a T-shirt. It’s also worth noting that the new construction looks more high-end—this is not the techy, shiny Helium of old.
The jacket’s low weight contributes to comfort with its barely-there feel, and its cut provides decent freedom of movement. The hood cinches down well, and a wire brim helps it retain structure. The cuffs are cleanly finished and the hem is adjustable, though the small zipper garage at the chin could offer more protection between metal and mouth. Overall, despite stripping down the features and design to the basics, Outdoor Research managed to retain sufficient all-day comfort with the Helium UL.
Breathability is the Helium UL’s biggest weakness. Despite Outdoor Research’s 20,000mm breathability rating, it falls well short of premium 3-layer shells featuring moisture-wicking liners and Gore-Tex membranes. It also trails behind competing ultralight designs like the Montbell Versalite, which manages moisture better thanks to pit zips. Notably, the Helium UL lacks pit zips, core vents, or other ventilation options, so once you start moving, moisture builds quickly.
I’ve used the Outdoor Research Helium UL primarily for running throughout the winter in Leavenworth, where temperatures have ranged from about 30 to 40 degrees (it’s been a mild one). I generally layer it over a synthetic tee or a thin merino base layer, and even then, it gets swampy fast. I certainly appreciate the lightweight nature of the Helium for running—I’d prefer not to run in a heavier jacket—but its breathability is a downside, and I have to consistently lower the front zipper to keep air flowing. In the end, it’s fine for short bursts of strenuous activity or light output, but I don’t recommend it for sustained movement in continuous rain.
This is where the Outdoor Research Helium UL absolutely shines. At just 5.7 ounces, it’s one of the lightest fully waterproof jackets you can buy—out of the rain jackets that Better Trail has tested, only the Rab Downpour Light (7.7 oz.) and the Montbell Versalite (6.4 oz.) come close. (We are in the process of testing the 2.5L Rab Phantom, which weighs a mere 4.1 oz.) The Helium UL packs down to roughly the size of a half-liter Nalgene, making it easy to justify carrying it on runs, climbs, fastpacking missions, any sort of travel, or ultralight backpacking trips where rain is possible but not guaranteed.
The Helium stuffs into its lone chest pocket (or the left hand warmer pocket on the women’s version), and rolling it into the hood works well enough if you’re lazy. It’s so small that you can stuff it in a crevice of your pack and forget about it until the sky opens up. All in all, while some other pared-down rain shells might outperform it, the Helium UL is one of the lightest, most compact waterproof jackets you can buy.
With a 15-denier nylon shell, the Outdoor Research Helium UL sits firmly on the fragile end of the rain jacket spectrum. It’s tougher than ultra-thin jackets like the Montbell Versalite (7D), but it doesn’t come close to the durability of a true 3-layer shell with a fabric backer. The 2.75-layer printed liner might improve the membrane’s longevity compared to the older Helium models’ 2.5-layer build—something we're monitoring over the long term.
That said, I’ve felt comfortable wearing the Helium while rock climbing around Leavenworth, Washington, and brushing against granite—more than I would with some thinner shells. Compared to well-known thicker and heavier shells like the Arc’teryx Beta AR, though, this jacket exists in a different universe. The Outdoor Research Helium UL is a “handle with care” piece, built for weight savings first and longevity second.
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Longevity
Choosing durable outdoor gear and keeping it in use for longer is one of the best ways to reduce environmental impact. Our proprietary longevity rating assesses factors like overall build quality, materials, fabric denier, component durability, and real-world performance. A green check indicates that we expect the product to be long-lasting relative to its peers, a yellow check mark indicates average longevity, and a red X indicates a product that may have a limited lifespan.
PFAS-Free DWR
Durable water-repellent (DWR) finishes can contain PFAS (per- and polyfluoroalkyl substances). These highly persistent “forever chemicals” are used in outdoor gear for their strong resistance to water, oil, and heat, but are linked to environmental contamination and a range of health concerns. A green check mark indicates the product uses a PFAS-free DWR, while a red X means the DWR contains PFAS.
PFAS-Free Waterproof Membrane
The membranes used in waterproof products such as rain jackets, ski jackets, and shoes can contain PFAS (per- and polyfluoroalkyl substances). These highly persistent “forever chemicals” are valued for their resistance to water, oil, and heat, but are linked to environmental contamination and a range of health concerns. A green check mark indicates the product’s waterproof membrane is PFAS-free, while a red X means it contains PFAS.
Recycled Materials
Recycled materials are prevalent in outdoor gear, with nylon, polyester, wool, and down among the most common, but the composition varies widely. A green check mark indicates the product is made with a substantial amount of recycled materials (100% recycled or the core fabric that makes up most of the product is recycled), a yellow check means it contains a moderate to small amount of recycled materials, while a red X means there are no recycled materials in the product.
Bluesign Approved
Bluesign Technologies, based in Switzerland, operates a third-party textile management system that ensures materials are manufactured to strict environmental, chemical, and worker safety standards. A green check mark indicates a product is either a Bluesign Product (contains at least 90% Bluesign-approved fabrics and 20-30% Bluesign-approved accessories) or features a significant amount of Bluesign-approved materials. A yellow check mark means it uses some Bluesign-approved materials but less than the aforementioned category, and a red X means there are no Bluesign-approved materials in the product.
Responsible Manufacturing
This criterion evaluates a brand’s commitment to fair wages, safe working conditions, and reducing environmental impact through certifications and programs like Fair Trade Certified, Fair Wear Foundation, Worldwide Responsible Accredited Production (WRAP), and the Fair Labor Association, while also recognizing brands that manufacture primarily in the U.S. or Europe under strict labor and environmental regulations. A green check mark indicates a brand meets our responsible manufacturing criteria, while a red X means it does not.
Recycled and/or Reduced Packaging
Packaging can add significant waste to outdoor gear purchases, so many brands work to reduce its impact by using recycled materials, incorporating Forest Stewardship Council-certified paper products, and minimizing plastic and paper use. A green check mark indicates a brand uses recycled or reduced materials across all of its packaging, a yellow check indicates moderate or limited use of recycled or reduced packaging, and a red X indicates the brand does not make either of these efforts.
Repair Services
Repair services extend the lifespan of outdoor gear and reduce overall consumption, though programs vary widely. Some brands offer comprehensive repairs for a range of issues, while others provide limited or no repair support. A green check mark indicates a robust repair program, a yellow check mark indicates limited repair services, and a red X indicates the brand does not offer repair services.
Resale and/or Recycling Services
Resale and recycling programs help keep outdoor gear in circulation longer and out of landfills, ranging from trade-in resale platforms that offer store credit to take-back initiatives that recycle products at the end of their usable life. A green check mark indicates a brand offers both resale and recycling programs, a yellow check mark indicates it offers one or the two, and a red X indicates it offers neither.
Carbon Footprint Tracking
This criterion evaluates whether a brand measures, reports, and works to reduce its greenhouse gas emissions using established frameworks such as the Higg Index, Greenhouse Gas Protocol, or The Change Climate Project. A green check mark indicates a brand publicly reports greenhouse gas emissions data, sets clearly defined reduction targets, and uses established tracking frameworks such as Higg or The Change Climate Project. A yellow check mark indicates the brand tracks emissions and outlines reduction goals but provides limited data, lacks science-based verification, or does not clearly report progress. A red X indicates the brand does not appear to track greenhouse gas emissions or provides so little information that its efforts cannot be verified.
Annual Impact Report
Annual impact reports provide transparency and accountability by outlining a brand’s sustainability efforts across areas such as material sourcing, greenhouse gas emissions, waste, water use, supply chains, and packaging. A green check mark indicates a brand publishes a detailed, brand-specific impact report that closely aligns with our sustainability criteria and leaves little room for ambiguity. A yellow check indicates a brand provides some relevant sustainability reporting but lacks detail in key areas or is covered only briefly within a parent company report. A red X indicates a brand does not regularly publish an impact report.
Hood
As you’ve probably gathered by now, the Outdoor Research Helium UL is extremely minimal. However, its hood is a strong point. It’s adjustable (as is the jacket’s hem), which is appreciated, and the hood itself is roomy enough to work over a helmet. A wire brim helps keep the front of the hood stiff and water out of your eyes.
Storage
Outdoor Research gave the men’s Helium UL a single zippered chest pocket, while the women’s version gets two zippered hand pockets. Some will see this as a downgrade, but for running and rock climbing, I don’t use hand pockets anyway. Anything stored there tends to bounce too much to be practical.
While my phone technically fits in the Helium UL’s chest pocket, I don’t love carrying it there either. The jacket’s ultralight construction offers very little structure, which means heavier items like a phone bounce noticeably while running. In practice, the pocket works better for small essentials like a credit card or key than for weighty items you want to forget about mid-movement.
Tester: 5’10”, 160 lb.
Size tested: Men’s medium
The Helium UL has a trim, athletic fit. There’s enough room underneath for a base layer and a slim midlayer—think a lightweight fleece or an ultralight insulated jacket like the La Sportiva Lumina 200—but it will feel tight over bulkier insulation. The streamlined cut helps keep weight down and prevents excess fabric from flapping, but it does limit your layering options.
For ultralight missions where minimal layers are the goal, the fit works well. If you want a rain shell to wear as part of a chilly weather layering system, though, you’ll need to size up or choose a different rain jacket.
Rab Downpour Light ($165): More Comfy, and More Durable
The Downpour Light is 2 ounces heavier than the Helium UL—a fair margin in the arms race that is ultralight gear—but what you’re giving up in grams you gain in other areas. The most noticeable one is how appealing the shell is to wear; the Downpour Light’s 2.5-layer Proflex exterior is stretch-woven, giving it excellent freedom of movement. Both the men’s and women’s versions of the Downpour Light have hand pockets that sit above a hipbelt, although, like the Helium UL, this shell also lacks pit zips. Both jackets are waterproof to a point and best used for passing showers. Our final take? Get the Helium for its weight, or save with the Downpour Light. For more, read our review of the Downpour Light.
Montbell Versalite ($285): Better at Banishing Sweat
If the Helium UL’s lack of breathability is a dealbreaker for you, check out the Versalite. Its 3-layer material is also rated to 20,000mm, but it's far more airy than the Helium UL’s construction. The Versalite also has pit zips, which is a coup in a shell this light—it weighs only 0.2 ounces more than the Helium UL. However, the Versalite’s 7-denier fabric is even thinner than the Helium’s, there are no pockets to speak of on the jacket, and it costs $60 more. As an everyday and emergency shell, we prefer the Helium. But if you need a jacket for working hard, the more techy Versalite wins out.
The lightest of the light, OR Helium excels as an emergency layer when showers are in the forecast. The latest UL model is a leap forward in comfort and style, but it sacrifices breathability and will soak through in sustained precipitation.
Weather Protection
Comfort
Breathability
Weight & Packability
Durability
Sustainability
Ideal for summer hikes and short stints up high, the Downpour is an ultralight shell that protects against light rain without much weight and bulk. The stretch-woven shell and soft backer boost mobility, comfort, and breathability. However, due to the lack of pit zips we don’t recommend this jacket for rigorous activity.
Weather Protection
Comfort
Breathability
Weight & Packability
Durability
Sustainability
From Japan-based Montbell comes an impressive ultralight rain jacket that packs in a ton of features at a very low weight. The breathable shell and pit zips make it more suited to high-output hiking than most of the competition, but you’ll want to be careful with the painfully thin shell fabric.
Weather Protection
Comfort
Breathability
Weight & Packability
Durability
Sustainability
Is the Helium UL for You?
The ultralight game is filled with compromises, and the Outdoor Research Helium UL fits right into that mindset. This shell is almost a no-brainer for carrying everywhere, even if it’s not raining, thanks to the level of waterproofing it offers despite its incredibly light, packable design. It's also better-looking and more comfortable than its predecessor, boosting appeal for travel, commuting, and everyday wear. However, the ground you’re giving up in terms of breathability and durability deserves consideration—if those traits mean a lot to you, you might want to opt for another, heavier shell.
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