Under Armour Mens Base 2.0 Legging
These aren't your grandpa's long underwear. The unique negative grid traps monster warmth without adding weight and it's smooth on the outside to let you layer. UA BaseTM 2.0 is the most versatile of the UA BaseTM thermals, built for basically anything you do outside. Running to hunting, the hill or the woods, this guy has got you covered.