Smartwool  Classic Thermal Merino Quarter-Zip Base Layer Top - Men's

My husband really likes this shirt for the style, fit, and comfort. Unfortunately, it seems like he got a faulty top because the navy blue dye transferred and ruined the drivers seat of his BRAND NEW car. Nothing will get the dye out. Very sad experience and wish we never bought the top. This should not happen. I do not recommend.

You get what you pay for. Merino wool is what I get to stay warm and dry. I ski side country stuff so I’m not exact dressed for hiking. I go hiking in alpine gear and I have to work, hard. I sweat like crazy but this material dries quickly and keeps me warm. Even on cold days on layer on the legs is all you need. Warmer days you don’t feel overdressed.

I have been wearing these Smartwool shirts for over ten years. Never had an issue with any of them. The reason I love these shirts - Warm, wicks moisture, quarter zip for rapid ventilation, true to size, easy care. Wash inside out in cold water (very little detergent or better, merino wool wash), NO softener (it destroys the wicking capabilities), tumble in a dryer on AIR ONLY (no heat). Finish by hang to dry. Hint: Hang upside down so you will not have those hangar "pinch marks" on the shoulders. These shirts are expensive. Why not take the extra steps to take care of them. Also, wash in similar fabrics. If you wash these merino shirts in rough fabrics like denim, they will PILL. I have some that I still wear from eight or nine years ago. They're great shirts.

I've been wearing these tops for many years and I think I owned more than 10. The design has changed over the years. The last one is not a progress though. I'm talking about how the sleeve attaches to the body. It used to be almost seamless now it is there and you can see it and worse you can feel it. The overall fit has changed to and now it's loose, and I'm not a skinny guy at 200lbs. You can also see it in the product advertising pictures if you compare the old and new. I do not like active underwear that is loose especially in the winter. It is still a good product but no longer an excellent product. Sometimes you should not mess with a good product. Or make one lose and one fit so people can chose. You want to change something? Change the colors. BTW all the vibrant colors are now gone.

I've had one of tops more than 10 years. It's still fully functional and just starting to develop wear and a few small holes. Decided to get one of these new ones and so far it seems as hard wearing as the original, although possibly it's too soon to tell. I machine wash them warm, with my regular (dark) laundry and hang to dry. They shrink a bit after a wash and loosen up again after a few wears. I'm 170-175 lbs, a fit 5' 10", and prefer the Large because I wear them over a tee shirt and the slightly loose fit works for me in that scenario.

Smartwool does everything right . I’m 6’1” and 215lbs XL fit just fine.

I've only warm this once, on an overnight backpacking hike, so I can't comment on durability. I was very pleased with the comfort and warmth. It seemed to wick well when hiking with it on in the chilly morning, but I remove layers before I start to perspire. I went to my local REI with purchasing the Moss-Fox Brown color in mind in size XL which my usual in most tops, but tried on size L in Deep Navy. The XL was a bit loose while the L fit more like a baselayer without being too snug, and I really liked the Deep Navy so went with it. I'm 6-1 with a 44 chest, and a bit overweight around the midsection.

Size was pretty perfect (medium, I’m 6’, 165lbs, lean muscular). I’ll sometimes wear alone or with a wool tshirt and it works either way. I wash it every once in a while (ok, every 3-4 weeks if needed). LOVE the fact it’s 100% merino. Wears like iron, and is super comfortable. The 1/4 zip works as a perfect vent when needed, too. I live near the beach and it’s perfect for zipping up to start a walk and unzip as you heat up. I have two of these and my wife has two. We wear them every day.

Bottom line: This base layer let me down on my Mt. Whitney hike. Expectation: Warmth and reliable sweat-wicking during a high-effort, cold, alpine climb. Reality: Fabric didn’t wick; sweat pooled and stayed on my skin. Result: I felt clammy while moving and even colder during breaks. Comfort: Damp, sticky, and distracting the whole time. Trust: I had high hopes, but it failed when it mattered most. Verdict: Not suitable for high-altitude, cold-weather hikes; needs far better moisture management and faster dry time. What I’d change: Use a truly wicking fabric (e.g., proven merino or technical synthetics), improve breathability, and ensure quicker drying.

The base layer firt really good. I'm 5'9 & 185 solid pounds and an extra large fit really well. Another base lyer can fit under this one. It's very wam.The down size is the price, it's too expensive.