Big Agnes V Notch UL 40°

The V Notch UL 40° is a warm-weather mummy bag positioned for summer trips and hot-climate backpacking, using PrimaLoft Hi-Loft Ultra Silver synthetic insulation rather than down — a choice that trades some warmth-to-weight efficiency for a fill that keeps insulating when wet and dries faster, useful in humid environments where a down bag's performance can suffer. At 622 g total with a 364 g synthetic fill, it stays reasonably light for a synthetic bag, though it will not match the packed size or weight of an equivalent-rated down bag. Manufacturer-rated to a 4°C limit temperature (no separate comfort figure is given, so treat the limit as a lower bound rather than a comfortable sleeping target), it is built around a full-length, two-way, left-side zipper and foot-box ventilation for warm nights, plus a DWR-treated nylon ripstop shell using recycled material. It suits three-season backpacking in mild climates and is a sensible choice for hikers who already own a colder bag and want a lighter, warm-weather option that also holds up better than down if conditions turn damp.