Silk is a little anachronistic compared to some of the flashy and fine tuned options that you see on this list, but it still has the advantage of being just about the most comfortable next-to-skin layer you can find. It’s also reasonably warm and odor-resistant. But that’s where most of the appeal stops- outside of use as a sleep layer there are much more practical and affordable options in synthetics. Pros Not quite as light or layerable as the diminutive lightweight category, they’re nonetheless still a fine choice underneath uninsulated snow pants or a waterproof shell when you’re out and about.

null Excellent all round Excellent quality, very comfortable to wear. I bought the medium. I am 5' 8, 32 inch waist and they fit well. There is plenty of room for longer legs of course, but I don't notice the excess fabric when wearing them.While lambswool is warmer than merino wool, it’s too scratchy to be worn next to the skin. To be effective, a base layer has to fit closely enough to carry away moisture but should be flexible enough not to restrict your movement. Extreme cold demands heavyweight base layers. The natural loft of merino wool traps air very efficiently, making it warmer than synthetics of equal weight. While synthetics may dry faster, merino is warmer and more comfortable when it does get wet. How much you want to invest in a pair of long johns is mainly concerned with the kinds of things that you’ll be doing in them. Unless you’re planning on doing some mountaineering or are an avid cold-weather sports enthusiast, there’s no reason to empty your wallet over a pair of tech-specced long johns.

Carefully engineered 3/4 length thermals with compression pants-like tightness that’ll keep you warm and super comfortable while pursuing high output activities Heat Holders men's thermal underwear is sure to keep you warm on even the coldest days. We believe that whatever you’re doing, inside or out, you should feel comfortable and content so you can enjoy life to the full.The name “long john” is supposedly a reference to the late 18th century heavyweight boxing legend John L. Sullivan, who favored wearing them in the ring. Long johns and by extension, other base layer categories, almost always have their fabric weight rating listed somewhere. The categories might not be hard-cut but are a dependable place to start your search barring no strong specific preference. The main job of any base layer is to keep you dry when sweat starts to build up. As as such, it’s one of the key factors you want to consider when deciding on your base layer bottoms. Since REI updated the Midweight Bottoms, there are even fewer attributes we can point to as weaknesses. This no-nonsense piece of gear gets the job done well enough and isn't looking to collect accolades. The performance is really hard to beat, considering the price. If you're in the market for a warmer layer, and maybe a softer and comfier one at that, it would be time to reach for a wool option like the Smartwool Classic Thermal Merino Bottom and leave these for a milder day.