Mountain Equipment Helium 400 Down Sheep Sack - 3-season - only 820 g

Lightweight, warm, compact – your down sleeping bag for three seasons

With the Helium 400, you'll experience the perfect combination of lightness, functionality, and warmth for your next microadventure. This high-quality down sleeping bag is ideal for trekking tours, backpacking trips, and bivouac nights in spring, summer, and autumn. The Helium 400 truly shines on bikepacking tours: its extremely low weight and small pack size make it the perfect choice for anyone who counts every centimeter of storage space and every gram on the go – without compromising on warmth. This sleeping bag will keep you reliably warm even on cool spring or autumn nights.

Ideal for backpacking trips and mountain adventures

Thanks to its light weight of just 820 g and its compressible pack size, the Helium 400 fits easily into any trekking backpack or bikepacking handlebar bag. The high-quality duck down filling (90/10, 403 g) with a fill power of at least 700 cuin ensures comfortable warmth – even when temperatures drop significantly at night. The robust, PFC-free Helium 20D outer fabric is made from 100% recycled nylon and reliably protects you from the cold and external moisture.

Temperature scale and practical assessment

The specification "Good Night's Sleep" at -2 °C is a manufacturer's recommendation – based on practical tests and experience – and complements the official EN 13537/ISO 23537 standard (T-Comf, T-Limit, T-Extreme).

What does this information mean exactly?
"Good Night's Sleep Temperature" = Temperature at which you can sleep comfortably without feeling cold – even with prolonged use or under real-world conditions such as:
✅ lightweight sleepwear
✅ thin sleeping mat
✅ possibly damp weather
✅ Fatigue or hypothermia due to daily stages

The official temperature scale according to the manufacturer:

✅ T-Comf : 2 °C (Eddy's temperature recommendation for this model is 4 to 7 °C)
✅ Temperature limit : -4 °C (limit for experienced sleepers)
✅ T-Extreme : -20 °C (emergency area, not suitable as a comfort zone)

Note on temperature perception
The temperature ratings are provided by the manufacturer and are standardized. In practice, however, they can vary – especially if you are exhausted, hungry, or wet. The quality of your sleeping mat also has a significant impact, as down compresses at the back and therefore provides less insulation. A good sleeping mat is therefore essential for a warm night.

Features and technical details

✅ Weight: only 820 g
✅ Filling: 403 g duck down 90/10, min. 700 cuin
✅ Outer material: 100% recycled Helium 20D, PFC-free
✅ Inner material: 100% recycled supersoft 20D, pleasantly soft
✅ Alpine Fit 2.0 for maximum efficiency and comfort
✅ Angled box chambers for optimal heat distribution
✅ Anatomically shaped hood with 5 chambers
✅ Thermal collar with Gemini system to prevent thermal bridging
✅ Foot section with 4 chambers for warm feet
✅ Zipper: 140 cm, with storm flap and insulating collar
✅ Compression stuff sack with roll-top closure & mesh storage bag

More freedom through flexible use

Especially on bikepacking tours or ultralight trekking adventures, every gram counts – and that's where the Helium 400 makes all the difference. You save weight without sacrificing comfort. And best of all: you don't need to buy an expensive down sleeping bag to start your tour.

If you opt for a flexible solution, you can conveniently test this sleeping bag with us. Rent your outdoor gear exactly when you need it – and decide later whether you want to keep it. Rent your outdoor equipment for the duration of your adventure and enjoy the peace of mind that comes with being perfectly equipped.

Outdoor equipment for your adventure:
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