The second highest-lofting down used in any of Sea to Summit’s sleeping bags or quilts. 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.

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. 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.

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/