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What is the Therm-a-Rest Parsec™ 20F/-6C Long Sleeping Bag?
The Parsec 20F/-6C is a high-performance sleeping bag for backpackers, mountaineers, and thru-hikers. It perfectly balances low weight, compressibility, and reliable warmth. Its roomy yet efficient shape provides comfort without sacrificing thermal performance, making it ideal for those pushing deeper into the wilderness in cooler conditions.
What is it made of?
Insulation
The Parsec is filled with 900-fill Responsible Down Standard (RDS)–certified duck down, one of the highest quality insulations available in the outdoor industry. Fill power measures the loft of down, or how much air one ounce can trap when fully expanded. At 900, the down used here is exceptionally efficient, providing maximum warmth with minimal weight. This ultra-premium fill creates a lighter and more compressible bag than lower-fill alternatives while delivering outstanding thermal performance.
A PFAS-free hydrophobic treatment helps the down resist moisture absorption, dry quickly, and maintain loft even in damp or humid environments where untreated down would typically collapse.
Shell and Lining
The shell and liner are made entirely from 100% recycled 20-denier nylon ripstop, offering durability, low weight, and soft comfort against the skin. The ripstop grid reinforces the fabric to resist tears and abrasions, ensuring long-term reliability without adding unwanted bulk.
Both the shell and lining feature a PFAS-free Durable Water Repellent (DWR) coating, allowing them to shed light moisture such as dew, condensation, or small spills. By using fully recycled fabrics, Therm-a-Rest reduces reliance on virgin materials and decreases the environmental footprint of the Parsec.
What are its features?
Zoned Insulation and Baffle Structure
The Parsec uses zoned insulation, placing more down in areas prone to heat loss (like the core and feet) and less in low-priority zones to reduce weight. Combined with an improved baffle structure, this ensures even loft and eliminates cold spots for consistent warmth through the night.
Toe-asis Foot Warmer Pocket
This insulated pocket in the footbox traps warmth around the toes, creating a dedicated microclimate that quickly restores heat to cold feet and increases comfort in cold conditions.
Draft Protection and Hood Design
A cinchable hood allows you to seal warmth around your head and neck, while draft-blocking features along the zipper and collar prevent cold air from sneaking in. These elements work together to maintain heat once you've warmed up inside the bag.
Practical Additional Features
An internal stash pocket keeps essentials like a phone, headlamp, or snack within easy reach. The smooth YKK anti-snag zipper makes entry and exit easy while protecting the fabric from damage.
For packability, the Parsec includes both a compression sack — to minimise packed size for travel — and a larger storage sack for preserving loft during long-term storage at home.
Comfort and Temperature Ratings
The Parsec 20F/-6°C is independently EN tested, offering a comfort rating of −1°C (29°F) for average sleepers and a lower limit of −8°C (18°F). This makes it suitable for cold-weather backpacking when paired with an appropriate sleep system.
Features:
- Ultralight warmth — for maximum loft with minimal weight
- Premium 900-fill hydrophobic down — for superior insulation in varied conditions
- Zoned insulation — for warmth where you need it most
- Toe-asis foot warmer pocket — for rapidly heating cold feet
- Recycled nylon shell and liner — for durability with reduced impact
- Internal stash pocket — for keeping essentials close at hand
- Cinchable hood — for retaining heat on cold nights
- YKK anti-snag zipper — for smooth entry and exit without damage
- Compression and storage sacks — for packability and long-term care