How to Choose Base Layers
REI Co-op Midweight Base Layer Half-Zip Top - Men's
$29.83Compared to $59.95*Save 50%
Hard-charging winter days start out cold, but you always warm up. The men's REI Co-op Midweight base layer half-zip top offers the warmth of long sleeves and the easy venting of a front zipper.
- High neck coverage with a half-zip front lets you open up for venting when you're working hard
- Recycled polyester/spandex fabric wicks moisture to keep you comfortable
- Smooth outer face lets layers slide on easily, while a brushed interior provides warmth
- Spandex adds the right amount of stretch while underarm gussets maximize your range of motion
- Flatseam construction reduces bulk and chafing
- Thumbholes hold your sleeves in place and seal warmth in
- Rolled-forward shoulder seams prevent abrasion from pack straps
- UPF 50+ rating
- Back length: 29 in.; Tall sizes: 31 in.
- Weight: 9.8 oz.
- Machine wash cold; wash separately, gentle cycle, remove promptly; do not use bleach or fabric softeners; tumble dry low
- Contains materials that meet the bluesign® criteria
- REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
- Made in a Fair Trade Certified™ factory
Imported.
View all REI Co-op Men's Base Layer Tops| Best Use | Multisport |
|---|---|
| Shirt Type | Partial-zip |
| Fabric | 92% recycled polyester/8% spandex (150-denier, 220 g/m2; bluesign approved) |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50 |
| Moisture Wicking | Yes |
| Underwear Weight | Midweight |
| Sleeve Length | Long Sleeve |
| Thumbholes | Yes |
| Gender | Men's |
| Sustainability | Contains recycled materials Fair Trade Certified™ factory Contains materials that meet the bluesign® criteria From a Climate Label Certified brand |
REI Co-op Clothing - Men's
| XS | S | M | L | XL | XXL | XXXL | 24 IN Waist | 26 IN Waist | 28 IN Waist | 30 IN Waist | 31 IN Waist | 32 IN Waist | 33 IN Waist | 34 IN Waist | 35 IN Waist | 36 IN Waist | 38 IN Waist | 40 IN Waist | 42 IN Waist | 44 IN Waist | 46 IN Waist | 48 IN Waist | 50 IN Waist | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chest | 35 | 36 - 38 | 39 - 41 | 42 - 45 | 46 - 49 | 50 - 53 | 54 - 57 | |||||||||||||||||
| Sleeve Length | 32 | 32.5 | 33 | 33.5 | 34 | 34.75 | 35.5 | |||||||||||||||||
| Waist | 27.5 | 28 - 30 | 32 - 34 | 36 - 38 | 40 - 42 | 44 - 46 | 48 - 50 | 24 | 26 | 28 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 38 | 40 | 42 | 44 | 46 | 48 | 50 |
| Hip | 33.5 | 34.5 - 36.5 | 37.5 - 39.5 | 41 - 43 | 44 - 46.5 | 47.5 - 50.5 | 51.5 - 54.5 | 32 | 33.5 | 34.5 | 36.5 | 37 | 37.5 | 38.5 | 39.5 | 40.25 | 41 | 43 | 44 | 46.5 | 47.5 | 50.5 | 52.5 | 54.5 |
| Inseam | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements.
SHORT: Some pants are available in short sizes, which generally means an inseam that is 2.5 inches shorter than regular sizes.
TALL: Some pants, shirts, jackets and parkas are available in tall sizes, which generally means an inseam that is 3 inches longer and a rise that is 1 inch longer, a shirt or jacket body that is 2 inches longer, a parka body that is 2.5 inches longer and sleeves that are 2.5 inches longer than regular sizes.
Capri or cropped pants have an intentionally shorter inseam—reference the technical specs instead of this chart.
Inseam is measured to the floor.
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Most Helpful Favorable Review
Love the color and the warmth.
sshoell2 years ago
Received free productI got this top in the early fall when the temps start to dip in the mornings. The REI Co-op Men's Midweight Base Layer Half-Zip Top was perfect for keeping me comfortable in the cool temps when I’m running. I like the zip that allows me to vent some heat when I warm up. And the color is fantastic. I’ve also used it as a base layer for a cool night at a football game and as a comfortable layer in a cold office. The size seems true, I got a medium and I’m 6’ 2” 175 lbs and it fits great. If you’re looking for a great midweight base layer at a great price, I would recommend this top.
sshoellReceived free product
Millcreek, Utah
18 people found this review helpful
Most Helpful Critical Review
Good midweight base layer
NatureCalls2 years ago
Received free productNice synthetic midweight base layer for hiking, camping, general city and outdoor wear.
Wore this out on numerous hikes in more chilly weather, and used as a sleeping layer during camping and for general wear around town. Good construction and very comfortable.
Thumb holes are a nice feature and fit well/easy to use keeping the sleeves around the wrist when needed.
NatureCallsReceived free product
San Francisco
5 people found this review helpful
Customer Images
sshoell
Received free product
Millcreek, Utah
Love the color and the warmth.
2 years ago
I got this top in the early fall when the temps start to dip in the mornings. The REI Co-op Men's Midweight Base Layer Half-Zip Top was perfect for keeping me comfortable in the cool temps when I’m running. I like the zip that allows me to vent some heat when I warm up. And the color is fantastic. I’ve also used it as a base layer for a cool night at a football game and as a comfortable layer in a cold office. The size seems true, I got a medium and I’m 6’ 2” 175 lbs and it fits great. If you’re looking for a great midweight base layer at a great price, I would recommend this top.
Age:55–64
Weight:150–175 lbs.
Height:6'2"
Yes , I recommend this product
Dan
Michigan
Comfortable for hikes and around the house
2 months ago
This REI Co-op Midweight Base Layer Half-Zip Top has quickly become one of my go-to pieces for cooler weather. I’ve worn it on several hikes in varying conditions, and it consistently delivers comfort and warmth. The fit strikes a nice balance: snug enough to layer easily, but not too tight. The fabric feels soft against the skin, and I really like the half-zip for adjusting airflow when I start to warm up on the trail. It’s held up well after multiple washes. Beyond hiking, I’ve found myself wearing it for early morning walks and even around the house on chilly days. For the on-sale price, this is a solid choice.
Age:35–44
Weight:150–175 lbs.
Height:6'0"
Yes , I recommend this product
knot_emotion
Received free product
Seattle, WA
Perfect for fall hikes
2 years ago
This base layer has been great for fall hiking. It's warm for starting out on cool mornings in the mid-50s. With the breathable fabric and zipper, I don't overheat once I get moving and the temperature starts rising. I tend to sweat a lot and I haven't had any issues with overheating in this base layer. There is a little extra height in the collar that could be useful for keeping the neck warm in cooler conditions, but I've actually found that collar to be most useful for providing some SPF on the back of my neck, which I appreciate. The fabric feels good on the skin, soft enough for wearing my baby in a carrier on more mellow outings. The flat seams have prevented any hotspots under backpack or baby carrier straps. I've also been really pleased with the cut and the color. It looks casual enough that I don't mind wearing it around town after a hike. I'm 5'10" with wide shoulders and about 150 pounds, and the medium fits me snugly, just right for layering, but not so tight that I feel self-conscious without another layer on top.
Age:35–44
Weight:125–150 lbs.
Height:5'10"
Yes , I recommend this product
DLiT
Chicago, IL
Great for cold weather!
1 year ago
I worse this for 72 hours while knocking out a short thru hike of the Des Plaines River Trail (53.7 mi) in Illinois in late March 2024. Temps during the day were low 30's, and at night it dropped to high 20's. I worse this during the day with a thin North Face rain jacket and I was plenty warm while hiking, and even during rest periods. I also slept in this inside a 20 degree sleeping bag, and I didn't need any additional layers (under or over this shirt). Kept me warm, dry, and didn't smell even after 3 days and more than 50 miles of hiking. Great piece of gear!
Age:35–44
Weight:125–150 lbs.
Height:5'3"
Grandpa Harold
Excellent UV protection for hiking
1 year ago
Wicking fabric with long sleeves and zippered neck provides excellent protection against excessive sun U-V exposure. This is my first long-sleeve shirt for hiking, and it performed well in 101 degree at 5,000-6,000 ft elevation. With my wide-brimmed Tilley hat, I had no sunburn areas at the end of the day. My only request: Make the shirt available in lighter colors for Summer use.
Jacob
Denver, CO
Nice piece. A new staple.
2 years ago
First of all I got this in black, which in hindsight was probably not the best choice for summer hiking. That being said, I have been pleasantly surprised by how well this has performed in warmer conditions. I wore it backpacking in the Colorado mountains in 75 degree sunny weather and did not feel too hot, and my back didn't feel sweaty. It also kept me comfortable down to about ~45 at night before I felt the need to put on a fleece. It's really comfortable against my skin, and looks pretty sharp. This is definitely going to be my new go-to for hiking and backpacking. It's comfortable enough and fashionable enough that I'll even probably wear on chilly fall/spring days around town. Really really happy with my purchase.
Age:25–34
Weight:175–200 lbs.
Height:6'2"
Yes , I recommend this product
Akadventurer
Northern Alaska
Warm soft and dry.
9 months ago
Warm and wicking, soft and comfortable, but lightweight. Worn for 7 days straight on a hunting trip only time I was clammy was when drastically over working for the layers above it. Obviously no heat powerhouse, but it adds that "just enough" to take the edge off. Thought I'd hate the thumb hole loops, but they're a great addition, very "handy". Sized accurately, fit my big fat frame good. A tall size would be welcome, but its not overly short either.
Age:35–44
Weight:275–300 lbs.
Height:6'2"
Yes , I recommend this product
BobD
Received free product
Woodbury, MN
Great gear for cool mornig walks
2 years ago
The half zip is a true to size fit and is very comfortable to wear. The fabric feels very nice on the skin and controls body temperature exceptionally well. I am one that gets over heated quickly on hikes & walks, but with this product I was comfortable the whole time.
Age:65–74
Weight:150–175 lbs.
Height:5'7"
Yes , I recommend this product
Steve Bicknese
Alameda CA
Good but I miss the smooth layer of the old top
2 years ago
While this is generally a good baselayer, I miss the "slick" fabric in the baselayer top this replaces. The smoothness of the fabric in the replaced baselayer top allowed you to easily take off an outer fleece layer without the baselayer coming with it.
Height:5'11"
Age:75 or over
Weight:175–200 lbs.
Yes , I recommend this product
Kurt Colorado
Grand Junction, CO
my favorite shirt
2 years ago
I love this shirt. It feels so comfortable against the skin. It is warm in a range of temps from around the house or office to outside temps of 20 degrees (wearing winter jackets, etc, of course). And even after wearing multiple days (mainly at work) it doesn't smell like sweat! I don't use the thumb loops in the sleeves, so I kind of dislike that extra fabric under my hands when I am typing at my desk. But it's not a big deal.
Age:55–64
Weight:150–175 lbs.
Height:5'8"
Yes , I recommend this product
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