The Mountain Equipment Helium 400 Regular Down Sleeping Bag (2023) uses 403g of minimum 700-fill power DOWN CODEX-approved duck down and a high-performance, 100% recycled Helium 20D outer fabric, the Helium 400 is warm, lightweight and ultra-compressible for easy packing. Efficiently sized, supremely comfortable and very low in weight for backpacking and cycle touring while still being warm enough to cope with chilly nights.

Slant-baffle construction through the body maximises warmth, improves packability, and prevents down migration, keeping you warm night after night and preventing cold spots. At the foot of the bag, a four-baffle system focuses essential warmth around your feet, while in the hood, a five-baffle system optimises comfort and keeps the down precisely where it needs to be.

Inside the bag, a 100% recycled Supersoft 20D lining fabric with PFAS-free DWR offers breathability and durability for comfortable nights and a long lifespan, while a full-length Gemini™ entry zip baffle practically eliminates heat loss in this vulnerable area and is stiffened so it won’t catch in the zip. The low-profile magnetic Lode Lock™ closure and collar drawcords are practical and easy to use in the dark.

Designed with a technical yet comfortable Alpine 2.0 fit, Helium bags optimise thermal performance while minimising weight. With a Good Night’s Sleep Temperature of -5°C (23°F), the Helium 400 offers reliable warmth for travel to more northerly latitudes and for early spring and autumn use at higher altitudes.

Mountain Equipment Helium 400 Regular Down Sleeping Bag Features:

Insulation:

• Optimised baffle-by-baffle for maximum warmth-to-weight ratio.
• Regular: 367g of 90/10 Duck Down with 700 fill power.
• Long: 388g of 90/10 Duck Down with 700 fill power.
• Ethically sourced through DOWN CODEX© and RDS 3.0.
• Each bag includes a unique DOWN CODEX© code for transparency on sourcing and fill power.

Materials:

• Recycled HELIUM™ 20D: A lightweight (38gsm), recycled 20-denier fabric that balances durability, compressibility, and weather resistance. Densely woven for wind and heat loss resistance with a PFAS-free DWR finish.
• Supersoft™ Lining: 38gsm 20D recycled downproof nylon for breathability, durability, and next-to-skin comfort. PFAS-free DWR finish.

Patterning & Design:

• Designed for long-term durability and high performance.
• Women’s Alpine Fit: A refined, tapered shape with a zoned EXL® system that improves thermal efficiency while keeping the weight low.
• Slanted box-wall baffles: Reduce structural weight while optimising insulation.
• Strategic fill distribution: High-density fill in key areas (underside, hood, foot box) to prevent down migration and enhance warmth.

Foot box:

• Trapezium 4 System: A four-baffle design that enhances warmth and prevents compression around the feet.

Hood:

• Five-baffle construction for precise down control, low weight, and superior insulation.
• Spacious yet snug with dual tether drawcords to minimise heat loss.

Zip Baffles & Collars:

• Gemini™ Baffle System: A lightweight, low-profile design that minimises heat loss while maintaining protection.
• Lode Lock™ System: A secure, magnetic fastener with a mechanical lock for a one-handed quick-release closure.
• Integrated, adjustable down-filled neck collar for extra warmth.

Additional Features:

• Waterproof roll-top stuff sack: Maximises pack space and keeps gear dry.
• Storage Cube: Preserves down loft for better long-term performance. Ideal for at-home storage.

Mountain Equipment Helium 400 Regular Down Sleeping Bag Specification:

User Size:

• Regular: 185cm (6 ft 1 in) maximum user height
• Long: 200cm (6 ft 6 in) maximum user height

Weight:

• Regular: 820g (1lb 12.9oz)
• Long: 870g (1lb 11.5oz)

Insulation:

• Duck Down is ethically sourced via DOWN CODEX© and RDS 3.0.
• Regular: 403g of 90/10 Duck Down with 700 fill power.
• Long: 425g of 90/10 Duck Down with 700 fill power.

Temperature Ratings (EN13537/ISO23537):

• Comfort: 0°C (32°F)
• Comfort Limit: -6°C (21°F)
• Extreme: -24°C (-11°F)

Good Night's Sleep Temperature:

• -5°C (23°F)

Packed Size:

• 24cm x 21cm x 20cm (9.4in x 8.3in x 7.9in)

Manufactured in:

• Vietnam