The Kids' Capilene 3 Midweight Bottoms by Patagonia. The versatile and quick-to-dry Kid's Capilene 3 Bottoms made of fast-wicking 100% polyester (56% recycled) with Gladiodor odor control can be worn alone or with layers.
FEATURES of the Patagonia Kids' Capilene 3 MW Bottoms
Polartec Power Dry polyester insulates, breathes and wicks moisture; with Polygiene permanent odor control
My review of the Capilene 3 crew top is also applicable here:"Every year, I get at least one new Capilene set for each of my kids. The only times they're not worn is when in the wash or if they're rocking some of their Patagonia Micro D's. My kids love them because they are comfy and warm. You can get close to a full 3 seasons use out of them and they last a good long while. The sizing chart is accurate, at least in our case, but try some on them if you get a chance to verify size. I'll continue to buy both the kids and myself Patagonia Capilene as long as they're made. Definitely huge fans!"...just buy some already!
So I am a grownup, and this fits me, comically enough. I am 5'4" and about 100 pounds and I can easily wear the large. The only bad thing is they are sort of capri like, but that is nothing some socks can't fix. Why am I wearing the kids' version? They happen to be cheaper, and I just feel that the adult ones (and even these, for that matter) are really not that substantial to pay a lot of money for. Sure, this is very warm, and I have used it so far once or twice while camping. I plan to use it under pants this winter, as well. A good buy for sure.