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650+ Fill Power indicates that one ounce (30g) of down will re-expand to over 650 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.

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.

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.