850+ Loft Ultra-Dry Down
![850+ Loft Ultra-Dry Down](http://seatosummit.eu/cdn/shop/articles/Ultra-Dry_Down_850_a3c90dbf-ed91-4193-80bc-c0442da42776.png?v=1653006174&width=1200)
The highest-lofting down used in any of Sea to Summit’s sleeping bags. 850+ Fill Power indicates that one ounce (30g) of down will re-expand to over 850 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 the environmentally-friendly Ultra-Dry Down treatment.
All of which means you can rest easy.