Ascent Down Sleeping Bag (-10°C)

The third highest-lofting down used in any of Sea to Summit’s sleeping bags or quilts. 750+ Fill Power indicates that one ounce (30g) of down will re-expand to over 750 cubic inches after compression. Higher loft means that less down can be used to achieve the same temperature rating – important for performance sleeping bags. The loft and down quality/composition are independently tested by the International Down and Feather Laboratory (IDFL) – a copy of the certification is supplied with every Sea to Summit sleeping bag. The down is responsibly sourced and RDS certified and treated with our non-PFC Ultra-Dry Down™ treatment.

100% of the down used in our sleeping bags and quilts is independently certified to the Responsible Down Standard (RDS). The RDS certifies down against animal welfare requirements and tracks it from the source to the final product. The purchase of RDS certified products demonstrates demand for better animal welfare practices in the down and feather supply chain. Sea to Summit is certified to the RDS. To learn more about RDS visit https://textileexchange.org/standards/responsible-down/ 

Ultra-Dry Down is a non-PFC treatment hydrophobic treatment applied to the down during down processing. It is not a coating (which would reduce the ability of the down to loft), it comprises of very small particles of a polymer that cause the down clusters / feathers to repel water. Ultra-Dry Down is PFC and PFAS-free. Hydrophobic down is not waterproof; but it absorbs less water than untreated down and dries much more quickly.

Ultra-Dry Down does not affect the loft or lifespan of the down, or its breathability. The treatment will last through at least 20 washings.

Down and synthetic bags identified with our zip coupling symbol use a 65 inch #5 YKK full-length zip which allows a unisex left-handed and women's specific right-handed bag to pair together. Designed to pair side by side, each person sleeps in their own bag enabling each of you to take advantage of your bag's unique insulation zones, hood and footbox features - perfect for cozy adventures for two. Bags with full-length #5 YKK zips on both sides can also be coupled together with other pairing bags.

Our Free Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and multiple ventilation options when it's not. The (half-) zip on the right side of the bag (left side on women's bags) provides freedom of movement for both arms, additional ventilation and allows (the top third of) the bag to be folded down as a (mini) quilt when the mercury climbs higher than expected.