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Therm-a-Rest
Boost 650 Sleeping Bag: 20F Down

5 out of 5 stars
2 Reviews
$319.95 - $349.95

Style & Size:

Quantity


Boost 650 20F Sleeping Bag with adjustable warmth and shape for cozy three-season adventures

What Our Gearhead® Experts Are Saying:


“This sleeping bag is a backpacker’s dream—it’s warm, versatile, and easy to customize. The WarmZip feature lets me fine-tune the shape and temperature, and the arm holes add so much livability. Plus, it’s light enough for the trail and super cozy for chilly nights.”


From frosty spring mornings to crisp fall evenings, the Therm-a-Rest Boost 650 Sleeping Bag keeps us warm, comfortable, and ready for whatever the trail brings. Its semi-rectangular shape offers plenty of space to stretch out, while the innovative WarmZip™ system transforms the bag into a mummy shape, boosting warmth by up to 10°F when temperatures drop.


With hydrophobic 650-fill RDS-certified down and Zoned Insulation, the Boost efficiently distributes heat where it’s needed most, ensuring every night is cozy. Multi-use arm holes enhance ventilation and functionality, letting us adjust the bag or reach for our headlamp without leaving its warmth.


Lightweight and packable, the Boost 650 is perfect for backpacking adventures. Its eco-friendly shell and liner, crafted from 100% recycled nylon with PFAS-free DWR coating, add a sustainable touch to its exceptional performance. Whether we’re side sleeping, lounging in our tent, or stargazing, this bag delivers three-season comfort like no other.


Details

  • Versatile sleeping bag for three-season backpacking adventures
  • WarmZip™ system adjusts shape and adds up to 10°F for colder nights
  • Semi-rectangular design offers spacious comfort for side and restless sleepers
  • 650-fill RDS-certified hydrophobic down with Zoned Insulation for warmth
  • Arm holes add livability, ventilation, and easy access to gear
  • Eco-friendly shell and liner crafted from 100% recycled nylon
  • PFAS-free DWR coating and hydrophobic down for performance in wet conditions
  • Includes cinchable hood, draft collar, anti-snag zippers, and two-way entry zipper
  • Item #PCW0005
Insulation
hydrophobic duck down
Shape
mummy
Zipper
full-length
Bag Length
[Regular] 80in, [Long] 85in, [Short] 73in
Venting
full-length zipper
Degree
20°F
Storage Sack
yes
Activity
camping, weekend camping, backpacking
Manufacturer Warranty
limited lifetime

What do you think about this product?

Overall Rating

5 based on 3 ratings

Review Summary

1 Stars - 0 reviews
2 Stars - 0 reviews
3 Stars - 0 reviews
4 Stars - 0 reviews
5 Stars - 3 reviews

Fits True To Size

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5 out of 5 stars

July 17, 2025

I loooove this bag. It

I loooove this bag. It is lightweight, comfortable, and super warm. I honestly feel like I would've been fine with a 30 degree bag because I mostly camp in the summer, but the big vent in the front and the arm holes make a big difference as far as cooling me off. Also. . . . . . the arm holes are super sweet. They make it so you can read a book or look at your phone before you go to bed. I've had a synthetic bag for years, and the feel and construction of this bag fell amazing. I don't backpack often anymore, but this bag is plenty light and comes with a compression sack to get it nice and small for packing. Would definitely recommend. Again, I love this bag.

Robert A.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

June 23, 2025

The roomiest backpacking bag everrrrrr

Familiarity:
I've used it several times
Size Bought:
Wide regular

I LOVE this bag!! I originally purchased a Nemo Disco in a wide after reading reviews it was made for side sleepers. However once I put that bag to the test it was so tight and constricting. I had tried out ThermaRest in store and loved it so much!!! It had so much room and compared to the weight it couldn’t be beat! I returned my Nemo disco and bought this instead! Absolutely love it!

lauren T
5 out of 5 stars

June 23, 2025

I recently spent 5 days

I recently spent 5 days camping out, this bag was great , very comfortable to sleep in, warm and roomy for a side sleeper. I recommend it often at REI.

Colson S.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site