Marmot CWM MemBrain

This bag is specifically engineered for extreme high-altitude expeditions and sub-zero conditions, rated down to -40 degrees Fahrenheit. If you are camping in moderate winter temperatures, this bag will likely be overkill and too warm for your needs.

MemBrain is a waterproof and breathable laminate that acts as a barrier against moisture and wind. It is designed to keep the down insulation dry from both external snow and internal condensation, which is critical when you are stuck in a tent for days during a storm.

The technical mummy silhouette is designed to minimize dead air space, which helps your body heat warm the bag more efficiently. While it is snug to maximize thermal retention, it is cut to allow for necessary movement during sleep.

Yes, high-loft down requires careful maintenance to retain its insulating properties. You should store the bag uncompressed in a large storage sack rather than a stuff sack, and only wash it using a specialized down cleaner when absolutely necessary.

The Long size is designed for individuals taller than 6 feet. If you are of average height, the extra length will create unnecessary dead air space at the bottom of the bag, which can actually make it harder for your body to keep the interior warm.