Merino Wool is a super strong natural fiber that's incredibly soft, will keep you warm in the winter and breezy-cool in the summer, and its natural moisture-wicking properties keep your feet dry and cozy. And that's just the fabric, before we add all of the sock tech features that come in every pair of Bombas. Women's Merino Wool Blend Calf Sock 8-Pack - Cocoa Purple Multi - Large - Bombas