Nemo Equipment Sonic Down Sleeping Bag

The Thermo-Gills are zippered vents on the chest that allow you to dump excess heat without unzipping the entire bag. This lets you regulate your temperature on milder nights without letting cold air rush in, significantly extending the bag's usable temperature range.

Yes, the bag uses 800-fill-power hydrophobic down, which is treated to resist moisture and maintain its loft better than untreated down. While it is not waterproof, it is designed to hold its insulating properties much longer in damp, humid conditions.

The Toester footbox is a specialized, waterproof section at the bottom of the bag designed to protect your feet from condensation that often collects against the tent wall. It adds an extra layer of insulation and moisture protection where your feet are most likely to touch the bag's exterior.

Yes, the Sonic is designed to accommodate users up to 72 inches, or 6 feet tall. If you are right at that height limit, you may find the fit snug, which is typical for a performance mummy bag.

The chevron baffle design is engineered to keep the down insulation evenly distributed across your body. By preventing the down from shifting or migrating to the sides, it eliminates cold spots and ensures consistent warmth throughout the night.

Despite its 0°F rating, the bag compresses down to 9.6 liters. While it is not an ultralight summer bag, it offers a solid balance of warmth-to-weight, making it manageable for winter trips where you need to carry heavier gear.