Zpacks 10f Classic Sleeping Bag

The Zpacks 10f Classic Sleeping Bag is an ultralight hoodless winter bag filled with 900 fill-power RDS-certified duck down, using 441 g of fill weight. In the Short/Slim size it weighs 581 g and carries a manufacturer temperature rating of -12°C (10°F), placing it firmly in 4-season territory for winter trekking and cold-weather expeditions. Its 3/4-length bottom zipper and tapered cut shave weight compared to a full-zip mummy bag, but the missing hood means the head needs separate protection — a warm hat is essential. The 0.51 oz/sqyd Ventum Ripstop Nylon shell carries a DWR finish that handles light moisture, though the down itself is not treated hydrophobic, so keeping the bag dry matters more than with water-resistant-down bags. This is a bag for experienced ultralight hikers who deliberately trade the convenience of a hood for a lower total weight at a given temperature rating, and who already have a head-insulation strategy worked out.