Temperature Rating: 5°F to -4°F (-15°C to -20°C)For extra ordinary conditions or expeditions the Softie? 15 Discovery is ideal. It provides maximum warmth in extreme temperatures yet still packs to a relatively small pack size when compared to comparable synthetic bags on the market. The Softie? 15 Discovery was born to serve those working and operating in Arctic conditions. Just like all the other Softie? Original Series of bags, this one was designed with the end user in mind that gives their all and demands the same from the gear they use!