Thermarest Hyperion 20 UL Down Sleeping Bag

Ultralight and packable mummy sleeping bag for three-season camping and backpacking. One of the lightest bags available, the 900-fill, water-resistant Nikwax Down sleeping bag keeps you warm and comfortable.

Therm-a-Rest says:

Weighing a mere 1 lb. 4 oz., the Hyperion defies the cold and provides better rest while moving through the mountains.

Built to provide a featherlight pack weight and high-performance warmth, the Hyperion 20F/-6C sleeping bag is among the lightest in its class without sacrificing an ounce of performance. The bag uses thermally-efficient box baffled construction in key areas to ensure warmth and comfort in an ultralight package. Designed with high-quality materials and Therm-a-Rest performance features like SynergyLink™ Connectors, the Hyperion keeps your pack light, giving you the freedom to move quickly in the backcountry. Storage sack and compression stuff sack included.

The Therm-a-Rest's Hyperion 20 Sleeping Bag is our lightest bag with a comfort limit of  -6C or -5C. This outstanding warmth to weight ratio is achieved by using the highest quality responsibly sourced down expertly zoned in a box wall construction. The bag is lined with ThermaCapture to trap body heat keeping you nice and toasty.

The bag only has a half length zip which saves weight and increases warmth but reduces venting ability. The bag comes with tiny (potentially flimsy) straps to attach the bag to a sleeping mat to reduce the chance of you wriggling off your mat in the night. These can be removed if you want to save a few grams. As you would expect with such a lightweight bag the pack size is very small.

- Reviewed by Ultralight Outdoor Gear

Help and advice:

• Ultralight: One of the lightest pieces in its class, the Hyperion sets a new standard for high-performance outdoor equipment
• 900-fill Nikwax Hydrophobic Down™: Stays drier and maintains loft 60 times longer than untreated down
• Unrivaled Packability: Lightweight materials and precise design allow for a smaller packed size than ever before
• Box Baffled Construction: Uses mesh walls to maximize loft and minimize cold spots in key areas
• Comfort Fit: Ergonomic shape and longer zipper provide a more human-friendly fit than other ultralight bags
• SynergyLink™ Connectors: Integrate the bag with a mattress for optimal efficiency and comfort; removable for versatility
• ThermaCapture™ Lining: Bag is lined to trap radiant body heat and retain warmth without adding bulk or weight
• Zoned Insulation: Maximizes warmth and saves weight by intentionally placing fill where you need it most, 70% on the top and sides with 30% on the back
• Responsible Down Standard Certified: Certification that ensures that the waterfowl in the down supply chain are treated humanely