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Smartwool Midweight Funnel Zip

rated 4.5 of 5 stars
photo: Smartwool Midweight Funnel Zip base layer top

This midweight zip top, made from SmartWool's NTS (next to skin) 250 g/sq m merino wool, can be used for days without building a noticeable smell, making it ideal for longer backpacking trips. It excels in different temperature zones, especially for cool to cold-weather conditions, or less active pursuits.

It also has stellar features like rolled and reinforced collars; a tight-fitting, efficient cut; and ample-length in the sleeves (appreciated by us tall folks).

SmartWool also makes lightweight (195 g/sq m) and microweight (150 g/sq m) NTS baselayers, which excel in warmer temperatures and more active pursuits. (See also my reviews of the Microweight Crew, Microweight Tee, and Microweight Bottom.)

A happy Review Corps tester


  • Long arms, ample coverage.
  • Bio-mapping construction puts lighter-weight fabric in high-sweat and high-movement areas, and heavier fabric where more insulation or support is desired.
  • Athletic cut keeps fabric close to skin, where it can remove the most moisture.
  • Lower arms have lighter-weight fabric to prevent constriction around wrists when wearing multiple layers of clothing.
  • Wool's natural odor prevention means less funk when compared to synthetics.


  • Sizing compared to microweight baselayers may be inconsistent.

Best For:

This is a mid-layer or cold-weather baselayer. It's best for hikers and long-distance backpackers who appreciate warmth, but want to move moisture quickly.


Close-up of shoulder on baselayer top.

Fabric & Fit

The sleeves are a perfect length and circumference, and the well-engineered thumb loop does not tug on the sleeve seam.

It has great stitching all around, without any loose threads. Raglan sleeves—where the seams connecting the sleeve to the torso are not placed on top of the shoulder—mean less chafing when worn with a pack.

The collar and cuffs are more than adequately reinforced. The shirt appears “cut in the round,” where the panels are sewn to contour the body’s curves more truly than traditional construction might, as well as to minimize seams under arms.

This top seemed to be incrementally larger than the SmartWool Microweight Crew and Microweight Tee tops I tested, more than I think would be appropriate if the garment was designed sized-up, and ready to accept a layer underneath. The neck is particularly loose, as is the torso in general.

The midweight (250 g/sq m) merino wool SmartWool uses is well suited to undergarments, more stretchy and supple than synthetic materials, with an excellent drape I don't find with synthetics. The fabric colors are bold and bright. This midweight zip-neck has a contrasting black-and-grey checkered pattern on the shoulders and upper arms, as well as around the inner collar, belying its alternate duty as capable mid-layer.

Close-up of midweight cuffs

Wicking Ability

I’m always carrying a pack weighing at least 20 pounds, and my patrols as a Wilderness Ranger for the Bureau of Land Management on the Western Slope of Colorado often involve intermittent periods of intense off-trail scrambling followed by leisurely on-trail walking.

The usual weather is 70-100°F, sunny, with little humidity. We get the occasional mid-afternoon Rocky Mountain rainstorm, and it can snow at any time in the highlands, so any baselayer I wear has to be able to capture, then disperse moisture very effectively.

In this respect, this baselayer performs well, especially under colder conditions, though it took longer to dry than the microweight layers I tested.


As a ranger, wearing a set of baselayers under my button-down uniform comes in handy on days when I patrol on foot. Since I’m in the field literally every day, discerning the differences between the two was as easy as comparing Monday’s observations with Tuesday’s. 

This layer usually kept me warm, with a few exceptions. Prior to the testing period, I wore a set of Patagonia Capilene 3 baselayers for about two years. The SmartWool top compared favorably to the Capilene in many respects.

On comparable days, this top was as warm as the comparable Capilene, due in part to the closer cut of the Smartwool, and the better coverage.

I often wear just a baselayer top for my morning 3-5 mile run. Wearing a Capilene top on runs usually means bringing a light pair of liner gloves, as the sleeves on my medium Capilene don't come down to meet my wrist. With the extra coverage and the longer sleeves on this top I could leave my gloves home on a recent run where I might have otherwise brought them. Not having to hold something in my hand is good enough reason to pick a garment with fuller coverage.

I also never missed the cold sweaty back that comes with every pause in physical activity when wearing the Capilene; the SmartWool layers seem to conserve that heat better, or, at least, don’t get cold when I stop to catch my breath.

Odor Resistance

The merino wool SmartWool uses does not build "the funk” as quickly as my Capilene 3. I actually make it a point to not wear any type of deodorant or antiperspirant on those days when I know I’ll be patrolling on foot, and on long days in the canyons, conditions can really stink up a shirt.

However, I can wear the SmartWool layers for days without washing, which is something I could never try with the Capilene.

In fact, a particularly strenuous 8-mile out-and-back in a place called Rough Canyon usually leaves the Capilene top in the laundry hamper. But on a recent visit while wearing the only the short-sleeved Microweight Tee under a pack, I came out smelling so fine that I wore it later on that day to the rock gym.

This is valuable to me as my days are often long and laundry is often low on my priority list. Plus, I just generally like the idea of having to spend less money on washing my clothes.


After approximately 30 days of wear and a dozen or so washings, this top hasn't stretched, shrunk, or otherwise deformed. All seams are intact, with no signs of fraying.

This Midweight top should give the average user a few seasons of regular use, which I think is a reasonable expectation for baselayers of this weight.


Find yourself wearing your baselayers for a week or more without a wash? Need a single set of baselayers to take you from deserts to mountaintops? Tired of shirtsleeves and pant legs coming up short? All of these are fine reasons to give the odor preventing, versatile, full length, merino wool baselayer offerings from SmartWool a go.

They can be worn alone under a pack without worry, and work perfectly to keep you warm when you want to be warm, and cool when cool is…well, cool.

The bio-mapping construction appears to effectively allow the garments to hug the body while keeping seams away from high-friction areas. They are not fragile garments, and do not need to be babied. That all of these garments can be washed and dried in normal home laundry machines is brilliant.

Testing Conditions

I tested the SmartWool men's Midweight Funnel Zip, Microweight Crew, Microweight Tee, and Microweight Bottom, all in size Medium.

Location: Canyons and highlands in and around the town of Grand Junction, Colorado, 3-5 mile in-town road runs in temperatures ranging from 45 to 85 degrees Fahrenheit, once a week. 3-30 mile hikes on and off-trail, in temperatures ranging from 40-75 degrees Fahrenheit, two or three times a week. 6-8 hour work patrols by foot, bike, and truck.

My Stats:

Weight: 165 lb

Height: 6'-1"

Chest: 37"

Sleeve: 33-1/2"

Inseam: 33"

Waist: 31"

Source: received for testing via the Trailspace Review Corps

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Price MSRP: $100.00
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