Alpine Down Sleeping Bag

850+ Fill Power indicates that one ounce (30g) of down will re-expand to over 850 cubic inches after compression.

The higher the Fill Power, the more the down will insulate for a given weight. This means that less down can be used to achieve the same temperature rating – important for compressible performance sleeping bags.

Every Sea to Summit down sleeping bag comes with a test report from the International Down and Feather Laboratory IDFL confirming the down loft and quality. All of our down is RDS certified responsibly sourced, and hydrophobically treated with a non-PFAS Ultra-Dry Down finish.

The QuiltLock™ system uses the snap locks located at the shoulder and foot end of Sea to Summit sleeping bags plus the quilt footbox / quilt straps to secure a quilt to the sleeping bag. This adds thermal performance and versatility to your sleep system: your integrated quilt now works for ultralight summer adventures and turns your three-season bag into a four-season sleep system.

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 textileexchange.org/responsible-down-standard/.

Sea to Summit sleeping bag fabrics and insulation are made without PFAS compounds. The non-PFAS DWR finish on the shell helps prevent the insulation from becoming damp if the bag comes into contact with moisture, such as tent wall condensation.Ultra-Dry Down is a non-PFAS hydrophobic treatment that absorbs less moisture and dries more quickly. It does not affect the 'breathability' or the lifespan of the down and lasts through at least 20 washings. The down used in our sleeping bags is responsibly sourced.Sea to Summit Dry Bags, Stuff Sacks and Compression Bags use a non-PFAS Durable Water Repellent finish to help shed water. Big River bags use a non-PFAS PU coating.

Our Free Flow zip design ensures your sleeping bag retains maximum warmth when needed and offers multiple ventilation options in warmer temperatures. The half-zip on the right side of the bag (left side on women’s bags) provides freedom of movement for both arms, offers additional ventilation and allows the top third of the bag to be folded down.

Most Free Flow sleeping bags can be opened completely flat as a quilt.