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Marmot Reactor 2.0 Review

This simple, breathable fleece acts as a great layering piece at an excellent price
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Marmot Reactor 2.0 Review
Credit: Marmot
Price:  $105 List
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Manufacturer:   Marmot
By James Lucas ⋅ Review Editor  ⋅  Nov 14, 2022
  • Warmth - 20% 6.0
  • Comfort - 20% 7.0
  • Breathability - 20% 7.0
  • Layering Ability - 15% 7.0
  • Weight - 15% 9.0
  • Weather resistance - 10% 7.0

Our Verdict

The Marmot Reactor excels as a soft and warm mid-layer for the adventurer who wants simplicity. With a solid fit, a few zippered pockets, decent weather resistance, and an ability to wick when hot, the Reactor layers well making it ideal for backcountry missions and for casual hangs around town. Though hoodless and without thumbholes, this jacket is fairly comfortable and is easy to throw into a pack for a day out. For a warm and casual layer, that has an incredible warmth-to-weight ratio, this jacket does the job.
Easy to layer
Thin with lower warmth
No hood
Few features

Our Analysis and Test Results

The lightweight comfort of the Marmot Reactor 2.0 makes it a great jacket to throw into the top of a pack, wear around town, or take on casual hikes. The two zippered handwarmer pockets and the sizeable zippered chest pocket provide ample storage. The flap behind the zipper help battle the wind. Constructed from Polartec Classic 100 Micro, this fleece feels soft and comfortable against the skin. While it lacks a hood and some of the more technical features of the fleeces in this review, this jacket provides simple warmth in a cozy piece.

Performance Comparison

marmot reactor 2.0 - a comfortable jacket with polartec classic 100 fleece, the reactor...
A comfortable jacket with Polartec Classic 100 fleece, the Reactor features a nice chest pocket and two hand warmer pockets.
Credit: James Lucas


The Polartec Classic 100 Micro that makes up The Reactor feels light and warm. The wind flap behind the center zipper helped keep the biting cold from cutting through the jacket when our testers were hiking to the Flatirons in Boulder, Colorado. While the jacket lacks thumbholes to keep the sleeves down and in place, the elastic in the cuffs helps keep the wind from moving into the jacket. Some of our testers wished this piece was a bit thicker but overall it had a great warmth-to-weight ratio.


Feeling soft and cozy because of the Polartec Classic Micro 100, the Reactor scored well in the comfort metric. The jacket has an athletic cut and there is ample space for movement, which was appreciated when our testers threw on their backpacks for casual day hikes.

marmot reactor 2.0 - the lack of a hood means less weather resistance but the collar...
The lack of a hood means less weather resistance but the collar, which comes close to the chin, fights the cold well.
Credit: James Lucas

This fleece's simplicity helped with the comfort. The collar hits just below the chin and zips up completely while allowing for ample room to move the head. The arms felt a bit long and the cuffs' elasticity allowed our testers to easily pull them up to their elbows.

Weather Resistance

This jacket faired well in terms of its weather resistance and packability. Like all fleeces, the Reactor does get wet in heavier precipitation. While the wind flap behind the center zipper helped keep the wind away from the chest, the thinness of the fleece still allowed for air to cut through. The lack of a hood also made it harder for our testers to hunker down when the weather worsened.

This jacket did seem to fight light mists and rains better than the other fleeces in this review but if the forecast calls for anything more than a drizzle, you'll want to bring a heavier jacket that does a better job of fighting off precipitation.


With little excess material, this 10.9-ounce piece packed down small and took up little space in our packs while climbing, hiking, and heading into the backcountry. The jacket's plenty warm giving it an excellent warmth-to-weight ratio and making it excel in this metric.

marmot reactor 2.0 - with good warmth-to-weight ratio, the reactor did well as a fleece...
With good warmth-to-weight ratio, the Reactor did well as a fleece for literally warming up.
Credit: James Lucas


The thinness of the Reactor helps it breathe fairly well. While hiking out of the Owens River Gorge in Bishop California, around the Flatirons of Boulder, and while sport climbing in Rifle, Colorado, our testers felt comfortable in it. When they did start to sweat they either dropped the full-length zipper, pushed up the sleeves past the elbows or relied on the Polartec to wick away the excess heat from their bodies.

marmot reactor 2.0 - the thinness of the jacket made it quite breathable. our testers...
The thinness of the jacket made it quite breathable. Our testers would have liked a slightly more form fit for serious exercise but it held up well while racking up at the sport crag.
Credit: James Lucas

Layering Ability

While the thinness helps with breathability, the Reactor has marginal ability to be a stand-alone piece and functions better as a light piece under a shell. The athletic cut helped it to fit under a layer. Our testers do prefer jackets with thumb loops as they prevent bunching in the sleeves when putting on additional layers. Additionally, tighter fighting cuffs or sleeves would have helped alleviate this problem. The lack of a hood makes it layer better for layering but it also decreases the overall warmth of the jacket. Overall, the piece does well in terms of layering.

marmot reactor 2.0 - the lack of thumb loops make the jacket harder to layer with but the...
The lack of thumb loops make the jacket harder to layer with but the fit and the formed cuffs still work well for wearing the piece under a shell.
Credit: James Lucas

Should You Buy Marmot Reactor?

For early spring and late fall day hikes, this jacket makes an excellent choice. While the slightly bunchy arms and lack of a hood don't make it ideal for higher performance in the backcountry or out climbing, the stretch of the fleece make it usable in a bind. This jacket serves well in a pinch and its lightweight make it perfect for throwing into a pack. If you want a good value jacket with solid performance, the Reactor will keep you warm, it breathes well, and it'll layer like a champ.

marmot reactor 2.0 - this great value jacket offers solid warmth and a relaxing fit...
This great value jacket offers solid warmth and a relaxing fit, making it a smart choice when shopping for a fleece.
Credit: James Lucas

What Other Fleece Jackets Should You Consider?

The Marmot Reactor is ideal when worn under a shell on a gloriously sunny spring day at the ski resort. The price of this jacket makes it a good choice. However, the Outdoor Research Vigor Full Zip costs even less and offers a higher level of performance. It's great for layering purposes and it's more breathable than the Reactor.

James Lucas