Therm-a-Rest Boost 650 32F/0C Sleeping Bag

From backpacking trips to car camping excursions, the Therm-a-Rest Boost 650 32F/0C sleeping bag offers comfort for sleeping well outdoors. Plus, you can adjust its shape to add warmth when needed.

Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.

Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.

• Designed to be comfortable when you're falling asleep, when you're asleep, and when you're wide awake and hanging out in your tent
• Built to backpack, the materials and design are dialed in to make the bag lightweight, packable and high-performing in variable backcountry conditions
• Semirectangular shape gives you considerably more internal space than a mummy bag—you'll feel unrestricted and free to sleep in whatever position you want all night long
• Shell and liner are made of GRS-certified, 100% recycled, soft-to-the-touch nylon
• PFAS-free durable water repellent (DWR) coating and the hydrophobic down keep you warm and comfy even in wet weather
• Zoned insulation puts 650-fill-power down in key warmth-retention areas (on top, around your core and shoulders) and reduces it where it's less efficient (on the bottom)
• RDS-certified down
• Zipping up the WarmZip™ center zipper transforms the shape from a semirectangular bag to a thermally efficient mummy bag
• WarmZip pulls the down around your body and reduces the amount of space your body needs to heat, adding up to 10°F (6°C) to the bag's temperature rating
• Arm holes give you easy access to the WarmZip without having to use the side zipper and allow you to ventilate or comfortably sleep with just your arms out
• 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
• 2-way side zipper also allows for additional ventilation around your torso or down by your feet
• Puffy draft collar, a draft tube along the entry zipper line and a cinchable hood round out the Boost's bliss-inducing comfort
• Durable, antisnag YKK zipper pulls eliminate annoying snags and damaging tears
• Comes with a compression sack and a storage sack