The world's most in-depth and scientific reviews of outdoor gear

Mountain Hardwear Stretch Ozonic - Women's Review

Its status as an actually stretchy rain jacket sets this model apart.
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Price:  $200 List | $99.83 at REI
Compare prices at 4 resellers
Pros:  Stretchy (for real), soft, light, breathable
Cons:  Expensive, uncomfortable half-sized pit zips
Manufacturer:   Mountain Hardwear
By Lyra Pierotti ⋅ Review Editor  ⋅  May 16, 2018
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#6 of 10
  • Water Resistance - 30% 7
  • Breathability - 15% 7
  • Comfort - 20% 6
  • Weight - 15% 8
  • Durability - 15% 8
  • Packed Size - 5% 8

The Skinny

Mountain Hardwear nailed it with the Stretch Ozonic, and it's sure to be a trendsetter. The Ozonic is lightweight, feels light against the skin, and it is compressible for packing in your backpack. It has a few design flaws which keep it out of our award-winning category for now, but with some field testing, we are optimistic that Mountain Hardwear will iron out the details.

Comfort is a big plus with the four-way stretch of the Ozonic, and the fabric is some of the best we've experienced in rainwear--in fact, this jacket feels almost more like a soft shell. The Ozonic loses some comfort points with its half-sized, half-hearted, virtually useless and uncomfortably placed pit zips. But a rain jacket that feels like a light sweatshirt and breathes almost like a soft shell has, to say the least, a lot of potential.

2018 Product Updates
The Stretch Ozonic was updated this year! Keep reading to learn about the jacket's new features.

Compare to Similar Products

Our Analysis and Test Results

The 2018 Stretch Ozonic vs. the Older Version

Mountain Hardwear gave the Stretch Ozonic an update in the form of new pockets and an updated hood cinch. See the differences in the side-by-side photos, below. The latest version is shown in red on the left.

  • Updated Pockets — The new pockets are set on a slant a bit further back on the jacket and now feature storm flaps. There is also a new external chest pocket which the jacket can be stowed in for packability.
  • Hood Cinch — The older version had two hood cinches by the chin, while the updated model has a hood cinch in the rear of the hood.

Since we haven't tested the latest version, our review only pertains to the previous model of the Stretch Ozonic.

Hands-On Review of the Stretch Ozonic

The Mountain Hardwear Stretch Ozonic is in a category of its own--that is, within the category of rain jackets. It is unusual, novel, and has a lot of potential. It is well made, but some important details detract from the overall comfort.

Fending off chilly water droplets in ice caves in the MHW Stretch Ozonic  an unusual but useful application for a rain jacket.
Fending off chilly water droplets in ice caves in the MHW Stretch Ozonic, an unusual but useful application for a rain jacket.

Water Resistance

The weave and DWR finish of this jacket held up to our standard of water resistance. Our only complaint comes not from issues of leakage, but feelings of clamminess. This stemmed from the suppleness of the stretch fabric--the flexible material tended to cling to our skin when it was raining. Not our favorite feature.


The Stretch Ozonic's fabric breathes well enough for a rigorous bike ride in the rain. However, the pit zips are a travesty. They are half the size of standard pit zips, running along the inner arm and stopping short at the armpit. In our experience, it is far more effective to dump heat from the core of the body than the inner bicep. Presumably, Mountain Hardwear was trying to address the problem of rain getting in through the pit zips, which can happen--and admittedly, pit zips are not our favorite solution to breathability in a rain jacket--but we have seen far better solutions. The Outdoor Research Aspire - Women's introduced a novel solution that our reviewers largely appreciated: full side vents that zip open entirely and make the jacket into a poncho which breathes and provides a broad flap of coverage when biking, hiking, or even shopping.

In our ongoing compulsion to minimize the items in, and weight of, our packs, we found the Stretch Ozonic to be a crowd pleaser. In dry weather, the average breathability (combined with the stretchy fabric) allowed us to comfortably don this rain jacket as a wind layer when climbing, kayaking, hiking, or doing anything, really. And this takes us to our discussion on comfort…


A stretchy rain jacket? For real? Yes, for real. And it's soft and supple, too.

The stretch of the Ozonic jacket vastly improved the fit of the jacket, which often translated to better coverage in a driving rain or while riding a bike through a storm. The Marmot Crystalline used asymmetrical cuffs to provide a little more coverage to the arms; the Ozonic achieves the same result with a stretchy fabric that moves with you rather than riding up any time you move your arms to expose your under-layers to the rain. The arms are also a bit longer than the Crystalline, ensuring better coverage when you're out moving in the rain.

The many faces of the Stretch Ozonic.
The many faces of the Stretch Ozonic.

The stretch of the Ozonic, however, had a down-side. The flexibility and suppleness of the fabric meant it would plaster itself close to the body when riding a bike or walking in the wind. This often made us feel colder and more exposed to the elements, even though it technically still kept us dry.

The half-sized pit zips also proved mildly uncomfortable: the zippers end in the armpits and tend to chafe when we swung our arms walking, for example. Really, this jacket doesn't need pit zips, in our opinion. They just add bulk, weight, and awkwardness, in addition to the discomfort. The jacket is breathable enough without them. We would like to see this jacket re-engineered as a technical, minimalist climbing jacket much like the Outdoor Research Helium II but with stretch. That jacket would crush all of the competition.

Overall, the Ozonic needs some work on details that detract from the overall comfort gained by the stretchy fabric. Right now, it effectively breaks even in comfort gained and lost. With a few improvements, we see much potential in this jacket's design and manufacturing.


The Stretch Ozonic is relatively lightweight. It ranks as the heaviest of the ultralight rain jackets. At 8.4 ounces, it is still markedly lighter than the next closest category of competition, which starts at just over 11 ounces. It is just under three ounces heavier than the award-winning Outdoor Research Helium II, and just over two ounces heavier than the Marmot Crystalline.

Clever zipper selections: nice durable wide-toothed zipper for the often zipped front zipper  and waterproof taped zippers (less durable) for the pockets to keep your belongings dry.
Clever zipper selections: nice durable wide-toothed zipper for the often zipped front zipper, and waterproof taped zippers (less durable) for the pockets to keep your belongings dry.


The Mountain Hardwear Stretch Ozonic boasts one of our favorite features in a jacket: a wide-toothed zipper. This type of zipper is less amenable to a waterproof tape finish to keep your midline dry, so they include a storm flap to keep out rogue droplets. This is a zipper that will keep zipping, fast and easy, through many rainy store runs and stormy mountain adventures.

The stretch fabric also decreases the creasing tendency of the jacket (a common sign of wear in a rain jacket), and as such, improved the durability of the inner membrane.

Our only concern is of the long-term effect of sweating in this jacket. The suppleness of the jacket means it often rests against your skin, where it will pick up much more body oils. Our reviewers saw no decrease in waterproof/breathability over several months of testing, but over the lifetime of the jacket, we wonder if this could detract from the performance and durability of the two most important features of a rain jacket, clogging the pores that both breathe and block water.

Packed Size

It is not often that our reviewers climb with a rain jacket clipped to their harnesses: if the weather is looking dreary enough to want a rain jacket holstered for a quick draw, we're probably not doing anything too technical. So, is it really important to have a carabiner loop sewn into the pocket of a rain jacket? Not really. However, the Stretch Ozonic is a good example of a jacket that threatens to merge disciplines: it is so stretchy and breathable that we often took it along as both a wind and rain layer. We love being able to commandeer our gear for multiple, even if unintended, purposes. The Ozonic does not, however, have a clippable loop. Minor disappointment. The Outdoor Research Helium II, on the other hand, gives you no room to hesitate: It has a clippable loop and it packs in a very neat and tidy pocket which makes it an obvious choice as a wind jacket or a rain jacket. With the Helium II in our quiver, our wind shirts often stayed behind.

Comparing the packed sizes of (clockwise from top) the Marmot Crystalline  the Columbia Evapouration  and the Mountain Hardwear Stretch Ozonic.
Comparing the packed sizes of (clockwise from top) the Marmot Crystalline, the Columbia Evapouration, and the Mountain Hardwear Stretch Ozonic.

This jacket is quite compact when stuffed into its pocket, and stuffs much easier than both of the Columbia jackets in our review. Even though the two are now owned by the same parent company, Columbia has not inherited the easy packing feature.

Best Applications

Um, rain. That's the point. This is a great rain jacket for athletic pursuits, because it is so flexible and stretchy, but be wary of chaffing in the armpit from those ridiculous armpit vents. This is also a good multi-tasking jacket — you might give it a try as your wind AND rain jacket. It is certainly tougher than your average wind jacket and much more supple than most rain jackets. This is not your jacket for warm, wet climates, however. The jacket clings like saran wrap to your bare skin if you're only wearing a T-shirt underneath, and that skin (and oil and sweat) contact is not a good thing for the long term durability of a rain jacket.


Not exactly the bargain basement deal here. More top-of-the-line, price-wise. We do not think the jacket justifies the high price of almost $200. Not yet. But it will be a few easy fixes to get it there. The novelty of stretch in a rain jacket does not automatically double its worth. If Mountain Hardwear followed the design of the Outdoor Research Helium II, making the jacket a true minimalist rain-and-wind jacket but with STRETCH, we would be flabbergasted. Here's to hoping!


The Stretch Ozonic is a jacket to watch. If you buy it this year, you are very unlikely to be disappointed, but we are eager to see what next year's updates bring to the table. With a few comfort and design improvements, this jacket is likely to become a reviewer's favorite, and an industry trend-setter to boot.

Lyra Pierotti