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.

KEY FEATURES

1. Efficient, Tapered Design
Custom mummy silhouette cuts excess material for ultimate weight savings and packability.

2. 800 FP Down Insulation
Premium RDS-certified down is treated with a PFAS-free, hydrophobic coating and provides excellent warmth, weight, and packability.

3. Thermo Gill™ Vents
Featuring an interior and an exterior zipper with a draftblocking intermediate layer, each vent incrementally releases body heat without direct exposure to the cold.

4. Toester™ Footbox
Waterproof/breathable footbox utilizes a layer of synthetic insulation to protect the down from condensation and deliver maximum toastiness for toes. 

BEST USE
Winter Camping
Mountaineering

PAIR WITH
Chogori™ Mountaineering Tent
Tensor™ Extreme Conditions Sleeping Pad