Marmot Men's Bantamweight 15° Sleeping Bag

The Marmot Bantamweight 15° pushes toward the ultralight end of the mummy bag spectrum: 688 g total, built around 500 g of 900-fill-power hydrophobic goose down, rated EN/ISO to -3°C comfort and -9°C limit in what Marmot classifies as a 3-4 season range. Very high fill power paired with a modest fill weight keeps weight down without losing much warmth, reflected in a fill efficiency of about 1.8 g of down per gram of insulating power. Weight-saving choices show up throughout: a 7-denier nylon shell and liner (both DWR-treated), a half-length center zipper instead of full-length, and a continuous horizontal baffle rather than heavier box-wall construction. A draft collar and draft tube still limit heat loss despite the shorter zip, and an adjustable, fitted hood seals well around the head. The bag packs to just 35 x 16 cm, fits up to 183 cm in Regular, and is RDS-certified, made in Vietnam. At around 76 g per degree of rated warmth, this suits thru-hikers and ultralight backpackers who accept the thin 7D fabric's lower abrasion resistance for base-weight savings.