Ultra-comfortable backpacking down sleeping bag for warmer weather
Comfort isn't one-size-fits-all, so you can customize the shape of the Boost 650 to find the perfect balance between space and warmth. As a roomy, semi-rectangular sleeping bag, the Boost offers all the space you need for side sleeping, repositioning, spreading out and relaxing. The semi-rectangular shape offers much more space inside than a mummy sleeping bag. But more space requires more body heat to keep it warm, and cold is uncomfortable. This is where WarmZip comes in. When you open the WarmZip zipper in the middle, the Boost 650 transforms from a semi-rectangular sleeping bag into a heat-efficient mummy bag. It pulls the 650 filling down around the body and reduces the space the body needs to heat. With WarmZip you can increase the temperature of the Boost by up to 6 °C. Standard Therm-a-Rest features like a puffy draft collar, a draft tube along the entry zipper and a roll-up hood round out the Boost's comfort.
Features of the Therm-a-Rest Boost 650 20F/-6C sleeping bag:
- WarmZip™ Tech: patent-pending center-entry zipper design reduces the sleeping bag's interior space and insulates the body to increase warmth by up to 6°C.
- The choice is yours: Enjoy the roomy freedom of a semi-rectangular sleeping bag or the cozy warmth of a mummy sleeping bag - choose the shape and temperature you want with just one zipper.
- Multipurpose armholes: Reach for the WarmZip, read a book, play cards or simply air out - all without opening the sleeping bag.
- Fluffy warmth: A large amount of 650-fill, RDS-certified, water-repellent down creates insulation zones in key areas for maximum warmth - without adding weight.
- Eco-friendly: The outer material and lining are made from GRS-certified, 100% recycled, lightweight nylon and coated with PFAS-free water-repellent material.
- Other features: Non- snagging YKK zippers, collapsible hood, draft tube along zipper, thermal collar and two-way "step-in" zipper.
- Compression sack and storage bag included.
The Boost 650 is designed to be comfortable when falling asleep as well as when asleep and awake in the tent. The armholes allow easy access to the WarmZip without having to use the side zipper. They also allow you to access your belongings, read a book, play cards or high-five your friends without leaving the cozy warmth of your sleeping bag. Getting too warm? Use the armholes for ventilation or sleep comfortably with your arms outstretched. With the two-way side zipper, you can also ventilate around the upper body or at the feet. The Boost is equipped with a durable YKK zipper that prevents annoying snags and damaging tears.
All this comfort must be bulky and heavy, right? Wrong. The Boost 650 was built for backpacking - the materials and design were chosen to make it lightweight, packable and high performing in a variety of backcountry conditions. The zoned insulation places the water-repellent 650-fill down in the heat-retaining areas (top, around the core and shoulders) and reduces it where it is less efficient (bottom), so the Boost generates more warmth with less down. The outer and inner fabrics are made from 100% recycled nylon, chosen for its light weight and super soft feel. The PFAS-free DWR coating and hydrophobic down keep the Boost warm and comfortable even in wet weather.