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We're working out what we think - we'll add our view here!
Thermarest says:
Ultra-comfy warmer weather backpacking sleeping bag with adjustable shape and warmth.
From backpacking trips to car camping excursions, the Boost 650 provides the dreamy comfort you need to sleep well outdoors. With an innovative design that allows you to adjust its shape and add warmth when needed, the Boost is one of the most comfortable and versatile sleeping bags ever made. The semi-rectangular 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. But more space demands more body heat to warm it up and cold isn’t comfortable. That’s where WarmZip comes in. Zipping up the WarmZip center zipper transforms the shape of the Boost 650 from a semi-rectangular bag to a thermally efficient mummy bag. It pulls the 650-fill down around your body and reduces the amount of space your body needs to heat. WarmZip gives you the power to add up to 10F/6C to the Boost’s temperature rating. Standard Therm-a-Rest features like a puffy draft collar, a draft tube along the entry zipper line and a cinchable hood round out the Boost’s bliss-inducing comfort.
We designed the Boost 650 to be comfortable when you’re falling asleep, when you’re asleep and when you’re wide awake and hanging out in your tent. The arm holes give you 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 arm holes to ventilate or comfortably sleep with just your arms out. You can also ventilate around your torso or down by your feet with the two-way side zipper. Every zipper line on the Boost has a durable YKK anti-snag pull to eliminate annoying snags and damaging tears.
All that comfort must be bulky and heavy, right? Think again. The Boost 650 was built to backpack—we dialed in the materials and design to make it light, packable and high-performing in variable backcountry conditions. Zoned Insulation places the 650-fill hydrophobic down in key warmth-retention areas (on top, around your core and shoulders) and reduces it where it’s less efficient (on the bottom), allowing the Boost to create more warmth with less down. The shell and liner are made of 100%-recycled nylon that was handpicked for its light weight and super-soft feel. The PFAS-free DWR coating and the hydrophobic down keep the Boost warm and comfy even in wet weather.
Our Verdict
We're working out what we think about Thermarest's Boost 650 32F/0C Down Sleeping Bag, we'll add our comments here in due course.
- Reviewed by Basecamp Gear
Features
- Multi-Use Arm Holes: Organize belongings in your tent, reach over and let a little air out of your sleeping pad, play a game of cards, read a book and, of course, reach down and slide up the WarmZip—do it all without leaving the comfort of your sleeping bag with Boost 650’s arm holes. Plus, they offer another ventilation option on those warm nights under the stars
- Patent-Pending WarmZip™: With the center zipper down, the Boost 650 is a spacious and ultra-comfy semi-rectangular sleeping bag. Zipping up transforms it into a traditional mummy bag, pulling the insulation in around the sleeper to add up to 10F/6C of warmth. Space when you want it, warmth when you need it. That’s empowered sleep.
- Eco-Conscious: With RDS-certified, humanely sourced down insulation and 100% GRS-certified recycled soft nylon shell and liner fabric that’s coated in PFAS-free DWR, backpackers rest easy in the Boost 650 knowing they bought a sleeping bag with a reduced environmental impact.
- Semi-Rectangular Shape: The Boost 650 is wider and more spacious than any bag in its class, providing more freedom to move, twist, turn, side-sleep and get comfortable in the backcountry. If uncompromising comfort is what you want, then the Boost 650 is what you need.
- Comes with compression sack and storage sack
Specifications
Small
- Weighs (ex bag): 827g
- Fits: 168cm | 5ft 6in
- Girth (Shoulder/Hip/Foot): 160/150/155cm | 63/59/61in
- Fill Weight: 353g | 14oz
- Stuffed Size: 20 x 17cm | 8 x 6.5
- Comfort Limit: 41°F / 5°C
- Limit: 32°F / 0°C
Regular
- Weighs (ex bag): 921g
- Fits: 183cm | 6ft
- Girth (Shoulder/Hip/Foot): 163/152/155cm | 64/60/61in
- Fill Weight: 401g | 14oz
- Stuffed Size: 25 x 17cm | 9.5 x 6.5
- Comfort Limit: 41°F / 5°C
- Limit: 32°F / 0°C
Large
- Weighs (ex bag): 995g
- Fits: 198cm | 6ft 6in
- Girth (Shoulder/Hip/Foot): 165/155/155cm | 65/61/61in
- Fill Weight: 451g | 1lb
- Stuffed Size: 28 x 17cm | 11 x 6.5
- Comfort Limit: 41°F / 5°C
- Limit: 32°F / 0°C
Material & Construction
- 100% Recycled Nylon: Used on our Performance Fit sleeping bags, our soft-to-the-touch 20D nylon is 100% recycled and Global Recycle Standard (GRS) certified.
- Box Baffled Construction: To maximize thermal efficiency in key areas, we use mesh box baffles to boost loft and eliminate cold spots at the seams of the sleeping bag or quilt.
- YKK® Anti-Snag Zipper: Special slider design makes midnight ventilation a breeze by preventing annoying and costly snags on the fabric
- Eraloft™ Synthetic Insulation: Hollow fibers boost heat capabilities while shedding weight. Compressible synthetic insulation repels water and possesses excellent temperature regulation.
- Nikwax Hydrophobic Down™: Boasting unrivaled temperature regulation, it dries three times faster, absorbs 90% less water and maintains loft 60 times longer than untreated down.
- Responsible Down Standard: All of our down is certified to the Responsible Down Standard so that you can sleep easy knowing that the waterfowl have been treated humanely
- 650-Fill Duck PFAS-Free Hydrophobic Down, RDS
- 20D 100% Recycled Nylon Ripstop
