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Sonic™ Down Mummy Sleeping Bag


Typically Paired With:


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.



  • Award-winning design updated for even greater warmth retention and adjustability across temperatures.
  • Constructed with 100% recycled, bluesign® approved shell and liner fabrics.
  • Second-generation Thermo Gill™ vents extend the comfort range with a new multistage zipper system.
  • Overstuffed with premium 800 FP hydrophobic down that is PFC-Free and 100% Responsible Down Standard (RDS) certified, ensuring humane treatment and traceability throughout the supply chain.
  • Chevron baffle construction better compartmentalizes down for more uniform loft and down migration prevention.
  • Stretch construction at the knees for comfortable side sleeping.
  • Toester™ waterproof/breathable footbox utilizes a layer of synthetic insulation to protect the down and deliver maximum toastiness for toes.
  • Offset zipper creates a thermally efficient seal while an updated profile secures warmth closer to the body.
  • Protected by the NEMO Lifetime Warranty.

Included With Your Sleeping bag

  • Compression Sack