The Therm-a-Rest Boost 650 32°F/0°C Long (L) is an innovative, convertible down sleeping bag designed specifically for three-season backpacking and camp comfort. The "L" designation specifies the Long size, which accommodates campers up to 6 feet 6 inches tall (198 cm).

Unique Performance Highlights

• WarmZip Convertible Shape:
  The bag features a patented central zipper that changes the structural footprint. Left fully unzipped, it acts as a spacious, unrestricted semi-rectangular bag. Zipping it up cinches the insulation closer to your body like a thermally efficient mummy bag, which boosts the temperature rating by up to 10°F / 6°C.
• Multi-Use Arm Holes:
  Integrated, zippered openings on the sides allow you to stick your arms out to read, brew coffee, or manage gear without leaving the cozy warmth of your bag. They also function as additional ventilation.
• Zoned Down Insulation:
  Packed with 650-fill-power duck down treated with a PFAS-free hydrophobic coating, it retains loft and resists dampness. The down is strategically mapped on the top and sides where it retains heat most efficiently.

Specifications at a Glance

• Temperature Rating:
  32°F / 0°C Limit (Comfort rating sits around 41°F / 5°C).
• Sizing (Long):
  Fits up to 6'6" (198 cm). The total bag weight in this size is approximately 2 lbs. 7 oz. (1,099 grams).
• Materials:
  Light, ultra-soft 20D ripstop nylon shell and liner made from 100% recycled materials and finished with a water-resistant DWR coating.
• Hardware:
  Outfitted with smooth, anti-snag YKK zippers, a puffed draft collar, and a cinchable hood.