Comfort should be as unique as you are, which is why the Boost 650 lets you adjust its shape to perfectly balance warmth and space. Designed as a semi-rectangular sleeping bag, it offers plenty of room to side sleep, stretch out, or shift positions freely. Unlike a mummy bag, the Boost 650 provides more internal space for a less restrictive, more relaxed night’s sleep. But more space can mean more air to heat—something that’s not ideal when temperatures drop. Enter WarmZip. With its innovative center zipper, WarmZip transforms the bag from a semi-rectangular shape to a heat-efficient mummy bag, pulling the 650-fill down snugly around you and reducing the space your body needs to warm. This clever feature adds up to 10°F (6°C) to the bag's temperature rating, ensuring the warmth you need no matter the conditions. Add to that thoughtful details like a plush draft collar, a draft tube for the zipper, and a cinchable hood, and the Boost 650 becomes a new standard for sleeping bag comfort.

But comfort doesn’t stop when you wake up. The Boost 650 is designed for all moments in your tent life. Handy armholes allow you to adjust the WarmZip, access your gear, read, or even high-five your campmates—all without leaving the cozy warmth of your bag. Need some airflow? The armholes or the two-way side zipper make ventilation easy, keeping you comfortable through every part of the night. Plus, with durable YKK anti-snag zipper pulls, you’ll never have to fuss with annoying snags again.

Think all this comfort comes with extra weight or bulk? Think again. The Boost 650 is finely tuned for backpacking, offering lightweight, compact, high-performance design. Its Zoned Insulation strategically places the 650-fill hydrophobic down around your core and shoulders where it’s needed most, while reducing it in less critical areas. This smart design maximizes warmth without adding unnecessary weight. Crafted with 100% recycled nylon for both the shell and liner, the Boost 650 is as light and soft as it is eco-friendly. A PFAS-free DWR coating and hydrophobic down ensure it stays warm and cozy even in damp conditions.

FEATURES

• Customizable Comfort: Enjoy the spacious freedom of the semi-rectangular bag or the cozy warmth of a mummy bag—pick the shape and temperature that keeps you comfy at night with just a zip.
• WarmZip™ Tech: Patent-pending center 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 livability.
• Plush & Puffy: 650-fill, RDS-certified hydrophobic down is allocated to key areas with Zoned Insulation for refined heat efficiency and maximum coziness.
• 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.
  
• What's Included: Compression Sack, & Storage Sack

SPECIFICATIONS