Stay warm on those chilly nights with The Silk Sleep Sack which adds 10-12 degrees to your sleeping bag. This item is also ideal to use as a stand-alone sleeping sack when staying in hotels or anywhere you sleep. Made of 100% silk and silk is a natural and breathable material. The Sleep Sack provides a luxurious and comfortable sleeping environment. It also comes with an attached waterproof stuff sack which will prolong the life span of your Silk Sack and is great for storing your liner. Compare the Silk Sleep Sack to others and you will see our new features and discount pricing makes our liners a great buy. Each sack is 84 inches by 36 inches and comes in navy blue only. The stuff sack is 6 inches by 5 inches.