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The Outdoor Research Helium Rain Pants are built for ounce-counting backpackers and trail runners who want legitimate storm insurance without packing extra bulk. Weighing well under six ounces, these pants disappear into the corner of a pack until torrential conditions force your hand. They are ideal for summer alpine hiking, three-season backpacking, and trail running where severe rain is possible but not constant. Construction centers around Outdoor Research's lightweight Pertex Shield fabric, which delivers surprising wind and water rejection for such a whisper-thin textile. Independent testing widely praises its balance of packability and baseline weather protection. The minimalist design cuts excess hardware, relying on an elastic waistband and lower leg zips to keep the overall profile tidy and simple. The clear compromise comes down to abrasion resistance and long-term durability. The delicate face fabric will not survive bushwhacking through dense brush, sliding across granite boulders, or heavy alpine abuse. The lower leg zippers also require careful handling and might not clear bulky mountaineering boots. For standard trails, however, its weight-to-protection ratio is difficult to beat. **Highlights** - Ultralight build weighing under six ounces - Pertex Shield fabric for compact, reliable stormproofing - Packs down into its own pocket for easy storage - Elasticized waistband with drawcord adjustment - Ankle zippers to help clear standard trail running shoes **Watch-outs** - Thin shell fabric is susceptible to punctures and abrasive terrain - Limited venting options during sustained uphill exertion
Pros
- Weighs under six ounces, making it exceptionally easy to pack
- Pertex Shield fabric provides dependable wind and rain protection
- Packs neatly into its own pocket to take up minimal pack volume
- Streamlined elastic waist sits smoothly beneath a backpack hipbelt
Cons
- Delicate face fabric is vulnerable to tears from thorns and rocks
- Short ankle zips struggle to slide over bulky leather boots
- Lacks venting options, causing sweat buildup during hard climbs
Best uses
- Ultralight three-season backpacking
- Long-distance thru-hiking
- Fastpacking and trail running
- Emergency alpine storm protection
Specifications
- Weight
- 5.8 oz (men's) / 5.75 oz (women's)
- Fabric
- Pertex Shield nylon
- MSRP
- Approximately $170
- Waist Style
- Elastic with drawcord
- Leg Zippers
- Ankle-height lower leg zips
- Storage
- Stuffs into internal pocket
Pricing
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Full catalog listing & offersBest for
Ultralight three-season backpacking, Long-distance thru-hiking, Fastpacking and trail running, Emergency alpine storm protection
Where to buy the Helium
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The Outdoor Research Helium Rain Pants cater specifically to weight-conscious backpackers, thru-hikers, and trail runners who treat waterproof bottoms primarily as emergency weather insurance. At less than six ounces, this minimalist shell takes up almost no space in a pack, making it effortless to carry on three-season trips where severe weather is possible but not expected to persist continuously. Rather than loading the garment with heavy cargo pockets or full-length side zippers, Outdoor Research keeps the architecture exceptionally lean. The design relies on an ultralight Pertex Shield waterproof textile, an elasticized waist with an internal drawcord, and short ankle zips that allow deployment over trail running footwear. It deliberately cuts unnecessary features down to the bare essentials required to keep a hiker dry. That extreme weight savings comes with clear trade-offs in abrasion resistance and mechanical venting. The thin face fabric cannot withstand off-trail bushwhacking or abrasive rock scrambles, and the limited ventilation means interior sweat can accumulate quickly on steep, strenuous climbs. For ounce-counters staying on maintained paths, however, few alternatives match its protective efficiency and minuscule packed footprint.
Target Audience and Intent
The Helium Rain Pants are designed for backcountry users whose gear choices prioritize pack weight and compact volume above all else. Thru-hikers, fastpackers, and summer mountain hikers will find that these pants spend the vast majority of their lifespan packed tightly inside a rucksack rather than worn on the trail. For users who only need foul-weather protection during sudden mountain thunderstorms or unexpected cold drizzles, carrying a heavy pair of traditional rain pants makes little practical sense. The Helium bridges that gap by offering genuine waterproof barrier performance at a fraction of standard gear weights. Conversely, professionals working outdoors all day, trail maintainers, or hikers who regularly face sustained, multi-day coastal rain will find this minimalist garment insufficient for daily grinding abuse.
Materials and Construction
Outdoor Research builds the Helium using a proprietary iteration of Pertex Shield fabric, a technical textile engineered to deliver water and wind resistance with minimal bulk. The interior features a lightweight waterproof membrane backing, protected by fully taped seams to halt moisture intrusion along stitch lines. To maintain an ultralight profile, hardware is minimized across the board. The pant relies on a basic elasticized waistband secured by an internal drawcord, avoiding snaps, metal buttons, and a fly zipper. At the cuffs, short zippers provide just enough clearance to pull the hem over footwear. The entire garment packs down into its own internal pocket, compressing to roughly the size of an orange, making it one of the most packable emergency shells available.
Weather Protection and Breathability
In real-world trail conditions, the Helium provides dependable shelter against sudden downpours, sustained high winds, and chilly alpine gusts. The Pertex Shield membrane sheds surface water effectively when treated with an intact water-repellent coating. However, like nearly all ultralight laminates, breathability has distinct physical boundaries. Because the design omits thigh vents or full-length side zips, warm air has limited avenues to escape during high-output activity. On steep uphill slogs in muggy rain, internal condensation can build quickly against the smooth inner face, creating a clammy interior feel. Hikers managing heavy exertion in warmer conditions will need to regulate their pace to avoid sweating through their base layers from the inside out.
Durability and Field Vulnerabilities
The primary sacrifice of shaving weight down below six ounces is structural longevity. The face fabric used on the Helium is whisper-thin and cannot withstand coarse mechanical abrasion. Brushing up against overgrown briars, post-holing through crusted snow, or scraping against abrasive granite ledges can cause punctures or tears in the shell. Hikers who enjoy off-trail route finding, scrambling, or heavy bushwhacking should steer clear of this model. Even the lower leg zippers and seams require deliberate care to prevent snagging on lightweight textile edges. When maintained properly and reserved strictly for trail walking and camp shelter, the pants hold up adequately, but they demand significantly more user attentiveness than heavier alternatives.
Fit and Footwear Compatibility
The Helium features an athletic, moderately trim profile that layers well over running shorts, running tights, or lightweight thermal long underwear without excess billowy material catching the wind. However, it lacks the generous circumference required to layer over thick winter trekking trousers. Footwear transitions present another notable consideration. While the short ankle zippers open wide enough to pull the pant legs over low-profile trail runners and sleek approach shoes, trying to slip them over bulky mountaineering boots or stiff, wide leather hiking boots is frustrating and often requires unlacing footwear. Planning your footwear system beforehand is essential to ensure smooth transitions when rain hits suddenly on the trail.
Market Alternatives and Value
At around $170, the Helium commands a moderate price premium driven by specialized ultralight textiles rather than an abundance of features. Shoppers looking for lower-cost reliability often turn to mainstream alternatives like the Marmot PreCip Eco or REI Co-op Rainier. Those models typically cost under $120 and include full-length side zips for venting and easy boot entry, but they carry a severe weight penalty, often weighing nine to eleven ounces. On the opposite end, heavy-duty three-layer Gore-Tex shells offer far greater abrasion resistance and storm endurance, but at two to three times the price and double the weight. For ounce-counters, the Helium occupies a distinct sweet spot between price, protection, and ultralight packability.
How we picked
We started with a long list of rain pants that people actually buy, cut anything that could not clear our baseline for durability and field performance, then ranked the 10 that were left against the same criteria. Rankings are editorial. No brand pays for placement, and affiliate links never move a pick up or down.
- Fabric behavior over time
- Breathability, DWR life, loft retention, and how the piece performs after repeated washing.
- Real-world durability
- How the material, stitching, or steel holds up after a season of hard use — not how it looks new.
- Performance in bad conditions
- Wind, rain, cold, and grit are the test. Anything that only works on a nice day gets marked down.
- Weight and packability
- Every ounce has to earn its place in the pack, but not at the cost of something that fails in the field.
- Ease of use
- Setup, adjustment, and maintenance with cold hands, in the dark, without the manual.
- Value at its price point
- Compared against the closest competitors in the same tier, not against cheaper gear in a different class.
Helium — frequently asked questions
- Is the Helium worth it?
- We rank it #2 in Rain Pants. The Outdoor Research Helium Rain Pants are built for ounce-counting backpackers and trail runners who want legitimate storm insurance without packing extra bulk. Weighing well under six ounces, these pants disappear into the corner of a pack until torrential conditions force your hand.
- What is the Helium best for?
- Best for ultralight three-season backpacking, long-distance thru-hiking, fastpacking and trail running and emergency alpine storm protection. Standouts: weighs under six ounces, making it exceptionally easy to pack and pertex shield fabric provides dependable wind and rain protection.
- What are the downsides of the Helium?
- Delicate face fabric is vulnerable to tears from thorns and rocks, Short ankle zips struggle to slide over bulky leather boots and Lacks venting options, causing sweat buildup during hard climbs.
- What are the key specs of the Helium?
- Weight: 5.8 oz (men's) / 5.75 oz (women's) · Fabric: Pertex Shield nylon · MSRP: Approximately $170 · Waist Style: Elastic with drawcord · Leg Zippers: Ankle-height lower leg zips
- Target Audience and Intent — what should I know about the Helium?
- The Helium Rain Pants are designed for backcountry users whose gear choices prioritize pack weight and compact volume above all else. Thru-hikers, fastpackers, and summer mountain hikers will find that these pants spend the vast majority of their lifespan packed tightly inside a rucksack rather than worn on the trail.
- Materials and Construction — what should I know about the Helium?
- Outdoor Research builds the Helium using a proprietary iteration of Pertex Shield fabric, a technical textile engineered to deliver water and wind resistance with minimal bulk. The interior features a lightweight waterproof membrane backing, protected by fully taped seams to halt moisture intrusion along stitch lines.
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