MERINO BOTTOMS - A GODSEND If your ruck is heavy and your trek is long, unless it&&';;s Antarctica cold AF, you don&&';;t need a base layer on your legs. Your pants break the wind and your movement keeps you warm. But when the sun drops, or your movement is limited and your hatred of the cold rears its head, our merino long johns become a Godsend. They keep you warm when it&&';;s cold and they breathe when the sun reigns down again. Designed, tested, proven and built in the USA by American craftsmen and women, GORUCK Merino Bottoms come with our Scars Lifetime Guarantee.