Amplitude AmII (Fall 2022)

$379.00 - $399.00


The most room and ventilation options of any down bag available; 25° F

Ideal for adventures with a base camp, the Sea to Summit Amplitude AmII down sleeping bag brings spacious luxury and incredibly versatile ventilation options to wherever your travels may take you. Each side of the Amplitude has a full-length side zipper; a third zipper can be found in the foot box.
High-lofting down and quality construction keeps you cozy when it’s cold, and the zippers provide temperature regulation up to the point where you remove the upper section and sleep under it as a quilt.
The down is responsibly sourced and RDS certified and treated with the environmentally-friendly Ultra-Dry Down™ treatment.

Sleeping pad sold separately.


• ULTRA-DRY Down 750+ Loft 90% Down Cluster Premium Duck Down certified Responsible Down Standard (RDS)
• Vertical baffles over the chest to prevent down shift as you roll over in your sleep.
• A generous shape to allow you to sleep in any position without compressing the down insulation and creating cold spots.
• Full-length YKK® #5 main side zips and foot box zip provide unmatched ventilation and allow the top section to be removed and used as a comforter.
• Shaped hood and zipper draft tubes keep cold out and warmth in.
• Elasticated straps to attach to a sleeping pad of your choice
• Internal zipper pocket
• Form a snug sleeping bag for two by zipping to another Amplitude or Ascent™, Trek™, Traverse™, Altitude™, Journey™ or Venture™ sleeping bag.
• Includes lightweight Ultra-Sil™ compression bag.

Zip Coupling
Down and synthetic bags identified with Sea to Summit's 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.

ULTRA-DRY Down 750+ Loft
The second highest-lofting down used in any of Sea to Summit’s sleeping bags. 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 the environmentally-friendly Ultra-Dry Down™ treatment.

Responsible Down Standard
All Sea to Summit sleeping bags use only down which is certified according to the Responsible Down Standard (RDS). The RDS is helping shift the entire down and feather industry towards more humane animal rearing and handling practices. Overseen by the industry leading Textile Exchange, the RDS requires independent, third-party assessments of all aspects of animal rearing and handling throughout the entire supply chain. By purchasing only down that meets the audited requirements of the RDS, you can have confidence that each phase of the collection process has been completed with the welfare and ethical treatment of waterfowl in mind.
To learn more about RDS, visit

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