Best Long Underwear · #1
WarmWool Crew and Pants
Aclima
#1
WarmWool Crew and Pants
Aclima
Gear
Why it made the list
Norwegian 400 gsm double-face wool. The warmest true base layer sold, and it dries fast for the weight.
Where to buy the WarmWool Crew and Pants
We link straight to the manufacturer's own catalog for the exact make and model, plus Amazon where it's carried.
Some links are affiliate links. Buying through them supports our testing at no extra cost to you.
Full profile in progress
We're building out complete profiles for every pick on every list — specs, materials, real-world use notes, and photography. This entry is next in the queue. In the meantime, the ranked note above is our short answer for why it made the list.