I originally bought this to be used to keep condensation off my down bag in the winter, but have now used it wild camping/bivvying without a tent as it keeps you dry whatever! Although it is not very spacious, it is perfectly big enough to let a down bag
This bag is superb, very breathable and closes up well. The weight and cut are spot on, perfect for a 4 season down bag but might struggle with larger models. Packs up small and entirely waterproof.