Going Ultralight doesn't have to mean suffering, because we never skimp on our lightweight bags. We'd rather find a way to shave the weight and innovate on performance, like using Flex technology for our Nitro 30. We build in Flex between the shoulders and knees, so you get the comfort and thermal benefits, while saving precious ounces. Our smart Foot Box Venting lets you customize the climate in the lower half of your Nitro, without adding the weight of a full-length zipper. Ultralight speed with full-featured comfort.