Outdoor Research Helium II Rain Jacket Review

Overview

The Outdoor Research Helium II was, for the better part of a decade, one of the go-to minimalist rain shells for thru-hikers and fastpackers who wanted real waterproof protection without the weight penalty of a “backpacking” rain jacket. It’s built around 2.5-layer Pertex Shield fabric, skips almost every non-essential feature, and packs down into its own chest pocket to about the size of a fist. Outdoor Research has since discontinued the Helium II in favor of updated Helium lineup jackets, so this one is now mostly a secondhand or closeout find — but it’s worth understanding what made it a category staple in the first place.

Key Specs

Spec	Detail
Weight	181 g (6.4 oz)
Fabric	2.5-layer 30D Pertex Shield DS ripstop, 100% nylon with clear laminate
Fit	Standard
Center back length	79 cm
Pockets	Chest stow pocket (doubles as stuff sack), no hand pockets
Closures	YKK zippers, elastic cuffs, adjustable hem and hood
Status	Discontinued

Performance

Waterproofing and breathability. The Pertex Shield DS 2.5-layer laminate does what it’s supposed to for the conditions it’s designed around: the shell is made of 2.5-layer 30D Pertex Shield DS ripstop fabric with clear laminate, and while very lightweight, it still has an impressive array of features. Real-world feedback lines up with that — one long-term user noted this jacket provides good protection from moderate rain for up to a few hours before wetting out. That’s the honest ceiling for any 2.5-layer fabric this thin: fine for showers, squalls, and “I need to get to camp” situations, less fine for all-day monsoon-season slogging where a heavier 3-layer shell will hold up longer before the face fabric saturates and breathability drops off.

Fit and feel. Sizing runs true. One backpacking reviewer running a men’s medium said he liked the fit a lot, and the medium ran true-to-size for someone who normally wears mediums, describing the cut as close but not slim — what Outdoor Research calls “Standard”. There’s enough room to layer a light fleece or puffy underneath without feeling like a sausage casing, but it’s not roomy. On skin contact, one Trailspace reviewer noted the fabric does feel a little clammy, though it isn’t as bad as other plastic/wax rain jackets they’d owned — a fair way to describe most non-eVent, non-Gore-Tex Pro shells in this weight class.

Features (or lack thereof). OR pared this jacket down hard to hit 6.4 oz, and it shows. There are no hand pockets, no pit zips, and minimal adjustability. A Trailspace reviewer summed up the compromise well: this is one area where a few extra ounces wouldn’t hurt — the Helium II was designed to keep weight as low as possible, so OR cut the wrist adjustment straps in favor of elastic wrist openings. That same reviewer found the wrist openings a little larger than their wrists, letting water run in when arms were angled upward — a minor but real annoyance in a downpour. Backpackers.com’s reviewer had a similar gripe about the missing hand pockets, saying he’d dock the Helium for not having two standard side pockets, since it made it difficult to warm his hands, though he was quick to add he refused to blame a purposely simple jacket for his personal preferences — it does the job well for which it’s intended.

Packability. This is where the Helium II earns its reputation. Weighing in at 6.4 oz, it’s easy to find space for in your pack, and you can also stuff it into its own pocket for a self-contained stuff sack. Pack Hacker’s testers called it one of the lightest rain jackets available, packing down into the size of your fist, and noted it’s quite breathable, even when tested in a very hot and humid climate.

Durability. The thin 30D face fabric is the trade-off for the low weight. One reviewer put it bluntly: the fabric is very thin, so you may need to be careful wearing it — good for trail running, but not very durable for backpacking. That tracks with what I’d expect from a fabric this light: fine if you’re not bushwhacking or scrambling over granite in it, but not something to treat carelessly around pack straps, buckles, or brush.

Pros & Cons

Pros

• Genuinely ultralight at 181 g — barely noticeable in the pack
• Reliable waterproofing for showers and moderate rain
• Packs into its own pocket, no separate stuff sack needed
• True-to-size, standard fit that layers reasonably well
• Historically inexpensive relative to other ultralight shells (when available)

Cons

• Discontinued — only findable secondhand or in dwindling retailer stock
• No hand pockets, no pit zips, minimal venting
• Wrist elastic isn’t fully adjustable and can let water in at certain arm angles
• Thin 30D fabric wants babying, not rough treatment
• Will wet through on multi-hour, all-day rain rather than a quick squall

Who Should Buy This

This jacket made sense for ultralight backpackers, thru-hikers, and trail runners who wanted emergency-grade waterproof protection at the lowest possible weight and didn’t mind giving up pockets and adjustability to get there. If you can still find one secondhand or on a closeout rack at a reasonable price, it’s a solid buy for that use case — just go in knowing it’s a “get you through the storm” jacket, not an “live in it all day” jacket.

Verdict

The Helium II earned its reputation as an ultralight classic for good reason: at 181 g it delivers real waterproof protection with almost nothing wasted on frills. It’s not the jacket for someone who wants hand pockets, pit zips, or all-day foul-weather durability — for that, look at something like the Helium HD or a heavier 3-layer shell. But as a minimalist, pack-it-and-forget-it rain layer, it’s still worth hunting down on the secondhand market. I’d put it at a 7.5/10, docked mainly for the lack of features and the fact that you can no longer buy it new.