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Icebreaker Quantum Long Sleeve Zip Hood

rated 5 of 5 stars
photo: Icebreaker Quantum Long Sleeve Zip Hood long sleeve performance top

Smart design, adjusts to changing temps: Hood up for cold mornings, down as the sun rises and activity level increases. Breathable wool is naturally odor-resistant, can be used longer between washings if traveling .

Durable, functional, stylish and well-made. Recommended for active/exercise wear, travel, and layering.


  • Technical: lots of specialty features
  • Versatile: combines warmth with light weight
  • Secure pockets: zip closed to keep items safely inside
  • Thumb-slots to keep sleeves in place
  • Note: these features were on the original design: Media device pocket at chest w/opening for cord, Pockets/fabric at wrists can be converted into "mittens" to cover hands for added warmth.


  • Pricey—but you get what you pay for
  • Slim fit—runs a bit small for layering
  • New style ("Quantum II") has fewer tech features

Found the original design of this jacket at an excellent price several years ago, on sale at a local outdoor specialty retailer. I bought it primarily with travel in mind. I also liked the technical aspects of the jacket that make it functional over a range of conditions and activities. (FYI—the new design—the "Quantum II"—has changed a bit.)

It's heavier than what I usually wear at home. IceBreaker considers it a medium weight (260) technical jacket, that can be used under a heavier outer layer for "alpine" activities in cold weather. But it's warm enough on its own in moderate temps, and definitely warm enough for my home in Southern California while going for evening walks or bike rides.

The hood is small. It won't obstruct peripheral vision, and is designed to fit under helmets, which is good for biking as well as climbing. 

I have purchased other IceBreaker products, and have found all of them durable and comfortable—and a bit more stylish to wear during long overseas flights, as a "step up" from wearing sweats, and nearly as comfortable. I prefer breathable non-synthetic fabrics that can adjust to both changing cabin temperatures and new climates when flying between time zones, and that still look presentable after a long trip.

I like to pair the Quantum jacket with their all-wool Villa Pants, purchased online a few years ago (but now—sadly—discontinued). These items became my "flight suit" when I travelled around New Zealand. 

IceBreaker claims to get their wool from sustainable and humane sources. The fabric in this jacket is breathable, lightweight, and packs small (it weighs just under 16 ounces). It requires less frequent washing vs. synthetic materials that often get smelly after a day of vigorous activity. I usually hang mine up after a hike, to air out.

There is a more open/loose weave wool under the arms for increased breathability—sort of a modified "pit zip" design. There are thumb openings at the wrist to keep sleeves in place, and an unusual "fold" to the fabric at the wrists that is sort of a pocket (?) but I have used as a "mitten"—I unfold it over my fingers to keep my hands warm when I don't have gloves with me (not sure the QII has this design).

The jacket is not waterproof, but sheds light rain and kept me warm even when wet. Coupled with a simple nylon shell it was great for boating and walking. Under a light down jacket it helped keep me warm during an unexpected late-spring snowstorm.

The body of the jacket is a wool/lycra blend with a soft 100% Merino wool liner that feels good against the skin. It's long enough to cover the hips, and the new QII design offers a longer "drop tail" hem. Both designs keep it from pulling up and exposing the back while reaching/stretching or bending forward, e.g. while cycling. (Now that I think about it, that "tail" and the thumb loops make it a good outdoor yoga jacket.)

The zippers on the pockets are rugged and reassuring—you don't want to lose your keys, cash, cards, or cell during a run or hike on the trail. It's nice to zip things into place and know they'll be there after your walk.

Same for a small chest-level zippered pocket, designed for small phone/media players, with an opening for wired earbuds. (Note: apparently that pocket has been moved to hip level with the "Quantum II" model.)

Also nice for being out after dark: reflective stripes on either side of the zipper, and a reflective patch on the back to catch the light and let cars know you're there. (Once again: the reflective features appear to have been discontinued in the QII)

Final note: I sold technical outdoor gear & clothing for a living many years ago, and learned that the "first generation" of products like this jacket are often the best. The early prototypes may be "over built" with various features that, in subsequent designs, are then "watered down" if they don't reach the desired price point/profit margins. 

Not sure if that's why IceBreaker changed the features of the jacket, but if you find an old QI out there—grab it.

If those changes don't matter, and you like the new design, get the QII.


I've owned this jacket for 5 years. It's been on overseas trips and local hikes, and is warm, stretchy, and comfortable for long flights, and stylish enough to wear for casual outings. It's technical and functional for walking, cycling, hiking, and travel, and has worked well in cold and wet weather.

Source: bought it new
Price Paid: $100

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The Quantum Long Sleeve Zip Hood replaced the Icebreaker Quantum Long Sleeve Zip.


Price MSRP: $195.00
Historic Range: $69.95-$225.00
Fit Slim
Layer Mid Layer
Weight 543 g / 19.15 oz (large)
Fabric Weight 260 Midweight
Fabric Body-98% Merino Wool, 2% Elastane / Lining-100% Merino Wool
Price MSRP: $195.00
Current Retail: $134.00-$220.00
Historic Range: $21.75-$225.00
Reviewers Paid: $100.00
Fit Slim
Layer Mid Layer
Weight 433 g / 15.27 oz (medium)
Fabric Weight 260 Midweight
Fabric Body-98% Merino Wool, 2% Elastane / Lining-100% Merino Wool
Product Details from Icebreaker »

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