How to Choose Base Layers

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Game for any adventure, any time of year, the men's Smartwool Classic All-Season Merino quarter-zip base layer top is made from a lightweight jersey and built for comfort—even under your pack.
Shop newer versionImported.
View the Smartwool Classic All Season Product LineView all Smartwool Men's Base Layer Tops| Best Use | Multisport |
|---|---|
| Shirt Type | Partial-zip |
| Fabric | 88% merino wool/12% nylon |
| Moisture Wicking | Yes |
| Underwear Weight | Lightweight |
| Sleeve Length | Long Sleeve |
| Gender | Men's |
| Sustainability | Contains ZQ merino wool |
| S | M | L | XL | XXL | |
|---|---|---|---|---|---|
| Chest | 36 - 38 | 39 - 41 | 42 - 44 | 45 - 48 | 49 - 51 |
| Sleeve Length | 31 - 32 | 32 - 33 | 33 - 34 | 34 - 35 | 35 - 36 |
| Waist | 29 - 31 | 32 - 34 | 34 - 37 | 38 - 40 | 41 - 44 |
| Hip | 36 - 38 | 39 - 41 | 42 - 44 | 45 - 48 | 49 - 51 |
| Inseam | 30 - 31 | 31 - 32 | 32 - 33 | 33 - 34 | 34 - 35 |
Measurements are stated in inches.
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I’ve been wearing smart Wool products for the past 10 years. The 150 line was one of my favorites. However, this model/build is noticeably sheerer compared to earlier editions— great for high aerobic activities, but not necessarily good for retaining body heat in colder conditions. The fit is excellent, so I will keep it, and it will come in handy for cool to warm hikes and runs. But if you are looking for warmth, I suggest the classic heavy weight instead. In fairness to smartwool, this is advertised as all-seasons garment so this weight would be consistent with that purpose.
I was looking for a base layer that I could wear in Alaska. After using it for my intended purpose I’ve realized this is so comfortable and it’s a nice quality, but it’s definitely to thin. If you are thinking about getting this I would recommend a thicker weight.
Good quality and nice close fit - not baggy. Great for fall and spring on its own.