All Feathered Friends sleeping bags come with a large cotton sack for storage, as well as a small stuff sack for stowing your sleeping bag compressed, but if you want to compress your bag even more, you’ll need to purchase a compression sack. For optimal compression, aim for a compression sack size similar in volume to the stuff sack we provide for that bag (you can find your specific bag’s volume under the “packed size” listing on its information page). An Egret, for example, has a packed size of 9L, so you’d want to choose a 10L compression sack.