Sonic™

Breaking Barriers to Warmth and Comfort

Sonic™

Down Mummy Sleeping Bag

$779.99

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-20℉

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Regular

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Sonic is built to be the only bag you need from -20°F to 40°F. The Backpacker Editors’ Choice award-winning big-mountain bag offers exceptional warmth and tuneability with a reduced environmental impact. This bag features our next-generation Thermo Gill™ vents, with a new multistage zipper system that dramatically increases the usable temperature range of the bag and allows fine-tuning of comfort from within. Sonic’s chevron baffle construction better compartmentalizes down, eliminating migration and keeping the down evenly lofted. (Not to mention, it looks awesome.)

The shell and liner fabrics are 100% recycled fabrics and bluesign® approved, and the premium 800 FP hydrophobic down is 100% Responsible Down Standard (RDS) certified. Years of history in the field yielded detailed upgrades on this bag, including a perfected profile, redesigned draft collar, and bolstered draft tubes. Our proven Toester™ footbox keeps feet warmer, provides a waterproof barrier against tent wall condensation, and protects down from moisture while drying damp clothes inside the footbox. Adaptable to whatever the mountain throws at it, Sonic continues to reverberate as the ultimate extreme weather companion.

Exceptional warmth and adaptability support comfortable sleep across a wide range of cold‑weather conditions.
Built‑in temperature regulation lets you fine‑tune heat retention without leaving your bag, even as conditions change overnight.
Premium construction and thoughtful insulation design maintain consistent warmth and protection in demanding alpine and winter environments.

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Compression Sack

Drawstring Mesh Storage Bag

Features & Innovation

Integrated Thermo Gill™ vents extend the comfort range and create fine-tuned control with their multistage zipper system.

Filled with premium 800 FP hydrophobic, PFAS-free, RDS-certified down. Products certified to the Responsible Down Standard (RDS) contain down or feathers from farms certified to animal welfare requirements.