Like a thick woven lined with a t-shirt, this camping shirt is great for those days when it might be nice but it might also get cold later (read: camping). Brushed heavyweight flannel that's durable and warm. We wanted to make a flannel that was heavy enough to keep you really warm but light enough to layer. Voila. Colin is 6'1", wears a Medium, and in case you were jealous about how nice he looks in our tees....just know he puts them on in a really weird way. Sorry Colin, you know it's true.