The Killarney Trail is a roomy rectangle bag with an oversized hood. It uses a 2-layer construction to help eliminate cold spots and keep you warm. There is also a zipper baffle to help seal in your body heat. It is composed of a 100% cotton flannel liner and rugged cotton canvas outer. When it's time to store or transport the bag, it conveniently rolls up with the roll-up straps so it's easy to carry and doesn't take up too much room.