Patented, Award-Wining Mountain Hardwear Technology.
This innovation allows users to tailor the fit of their sleeping bag to the conditions or their personal preferences. Zip open the Quantum Expander panel to instantly add 8 in / 20 cm of girth to the bag. The panel is fully insulated, so it doesn’t create a cold spot, but it does make the bag roomier and airier to allow comfortable sleeping in warmer conditions. Zip the panel closed to return the bag to its snug, efficient mummy shape.