Therm-A-Rest Boost 20F / -6C Down Sleeping Bag

COMFORT ISN’T ‘ONE SIZE FITS ALL’, SO THE BOOST 650 LETS YOU CUSTOMIZE ITS SHAPE FOR THE IDEAL BALANCE OF SPACE AND WARMTH.

The Boost sleeping bag is designed to offer maximum comfort with its spacious semi-rectangular shape, providing plenty of room to side sleep, shift positions, and stretch out without feeling confined. Unlike a traditional mummy bag, the semi-rectangular shape gives you significantly more internal space, allowing you to sleep in any position you desire—whether curled up or fully stretched out. You’ll feel unrestricted and free to relax the way you want throughout the night. Of course, more space means more body heat is needed to stay warm, and that’s where the innovative WarmZip comes in, ensuring you stay cosy even in cooler conditions.

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KEY FEATURES OF THE BOOST 650

• Customisable Comfort: Enjoy the spacious freedom of the semi-rectangular bag or the cosy warmth of a mummy bag—pick the shape and temperature that keeps you comfy at night with just a zip.
  
  
• WarmZip™ Tech: Patent-pending centre zipper design zips up to reduce the bag’s internal space and tuck insulation around the sleeper to boost warmth by up to 10F/6C.
  
  
• Multi-Use Arm Holes: Reach the WarmZip, read a book, play cards or simply ventilate—do it all while tucked into your sleeping bag for elevated liveability.
  
  
• Plush & Puffy: 650-fill, RDS-certified hydrophobic down is allocated to key areas with Zoned Insulation for refined heat efficiency and maximum cosiness.
  
  
• Eco-Conscious Materials: Shell and liner are made of GRS-certified, 100% recycled, soft-to-the-touch nylon and coated with PFAS-free water repellent.
  
  
• Inclusive Sizing: Each length—Short, Regular, Long—is also available in a Wide width, so you get the bag you want in the fit you need.
  
  
• Additional Features: YKK anti-snag zippers, cinchable hood, zipper draft tube, puffed draft collar, and a two-way entry zipper.

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