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A refined ultralight shell built for fast miles in mixed weather
Outdoor Research says:
The Helium UL Jacket is built for fast-moving pursuits in unpredictable weather, delivering ultralight, waterproof, and windproof protection for hiking, trail running, and travel.
Made with Toray Dermizax™ 2.75-layer fabric and fully seam-taped construction, this jacket provides ultralight, reliable waterproof performance and breathable comfort during high-output activity in unpredictable weather. An adjustable hood with a brim wire offers dependable coverage, while YKK® Aquaguard® zippers and shaped, bonded cuffs with partial elastic seal out the elements. Reflective logos improve low-light visibility, and the chest pocket doubles as a stuff sack for easy, compact storage on the go.
Our Verdict
The Outdoor Research Helium UL Jacket sees a meaningful update for 2026, with the move to a 2.75-layer Dermizax fabric. At 159g (Medium), it remains firmly in the ultralight category, yet the new fabric feels more substantial than earlier Helium versions. Waterproof performance is reassuring in steady rain, and wind protection is excellent for such low weight.
The fit is trim without being restrictive. It layers neatly over a light midlayer, and the shaped cuffs with partial elastic seal well without digging in. The adjustable hood with brim wire holds its shape in the wind and gives dependable coverage.
Breathability is good for a shell this light, though sustained high output in humid conditions will still lead to moisture buildup, as expected at this weight. Packability is a strong point, with the chest pocket doubling as a stuff sack.
Overall construction feels improved, and the updated fabric appears more abrasion-resistant than older Helium shells while retaining a compact, fast, and light profile.
- Reviewed by Ultralight Outdoor Gear
Features
- Adjustable Hood with Brim Wire
- Elastic Drawcord Hem
- Left Hand Pocket Doubles as Stuff Sack
- Reflective Logos for Visibility
- Shaped and Bonded Cuff with Partial Elastic
- YKK® Aquaguard® Center Front Zipper
- YKK® Aquaguard® Zip High Hand Pockets
- Fabric Performance:
- Breathable
- Fully Seam Taped
- Ultralight
- Waterproof
- Windproof
Specifications
- Small weighs: 152g
- Medium weighs: 159g
- Large weighs: 169g
- XLarge weighs: 177g
Material & Construction
- Dermizax™ 2.75-layer waterproof fabric and fully seam-taped construction
