Cumulus X-lite 400

Cumulus X-Lite 400

Cumulus X-Lite 400 is an extremely light down sleeping bag for cold nights, built for adventurers who count every gram. As the warmest model in the X-Lite series – the lightest sleeping bags in the world as far as the weight-to-warmth ratio is concerned – it is the perfect companion for trail running, ultramarathons, bikepacking, and sport rock climbing throughout the extended three-season window.
The X-Lite 400 weighs only 575 grams, yet packs a full 400 grams of high-quality 900 Fill Power ethically sourced Polish goose down. With a comfort rating of -1 °C and a limit of -7 °C, it takes the X-Lite concept confidently below freezing: where the X-Lite 300 covers chilly shoulder-season nights, the 400 handles frosty early-spring and late-autumn conditions, cold high-mountain camps, and colder sleepers – at a weight that most three-season bags cannot come close to.
This remarkable weight is achieved through the use of Toray® Airtastic 19 g/m² – the world’s lightest down-proof fabric. The bluesign® certified 7-denier ripstop nylon shell with DWR finish keeps moisture at bay while remaining highly breathable and incredibly light.
The sleeping bag features a trapezoid chamber construction with separately filled front and bottom, which maximizes down loft and eliminates cold spots – a chamber design suited to the generous fill weight of this model. The close-fit mummy shape further improves thermal efficiency, delivering dependable insulation with an absolute minimum of material.
The 3D-shaped hood wraps efficiently around your head to seal in warmth on freezing nights – exactly where heat loss matters most at these temperatures. Two separate draw cords allow comfortable, intuitive adjustment even in complete darkness, without reaching for your headlamp.
Guided by a strictly minimalist design philosophy, the X-Lite 400 is free from unnecessary components that would increase its weight. Despite this, comfort has not been compromised. The anatomical shark-fin foot box supports the natural position of your feet, eliminates empty air spaces, and delivers maximum warmth in one of the most cold-sensitive zones of the bag.
The 2/3-length 3 mm YKK® zipper with two self-locking sliders allows the bag to be opened from the top or ventilated during warmer nights, while the partial length keeps the calf and foot area fully insulated. A down-filled insulating tube running along the zipper prevents heat loss in this area. For even colder conditions, the X-Lite 400 can be combined with other X-Lite series bags to extend its temperature range deep into winter.
Practical details complete the package: a lightweight stuffsack compresses the bag down to a compact 5-liter package, while the included storage sack keeps the down lofted between adventures.

For hikers, runners, and bikepackers who accept no compromises when it comes to pack weight, the Cumulus X-Lite 400 offers an unmatched combination of premium materials and radical minimalism. It is the ultimate choice for fast-and-light adventures on freezing nights – from frosty high-mountain camps to cold late-autumn bivies – where every gram and every cubic centimeter counts.

FEATURES

• Fill: 900 Fill Power ethically sourced Polish goose down
• Shell and liner: Toray® Airtastic 19 g/m², 7-denier ripstop, DWR finish (100% nylon)
• Fabric certificates: bluesign®
• Construction: Trapezoid chamber design
• Separately filled front and bottom
• Close fit mummy shape
• 2/3 length, 3 mm YKK® zip with 2 self-locking sliders
• Down-filled zip insulating tube
• 3D shaped hood design
• 2 different hood draw cords for comfortable adjustment in the dark
• Minimalist, weight saving design and components
• Anatomical, shark fin foot box design
• Can be combined with other X-Lite series bags
• Stuffsack and storage sack included

MEASUREMENTS

Maximum user height: 185 cm
Length: 202 cm
Width (top/bottom): 77/42 cm
Weight of unfilled sleeping bag: 175 g
Stuffsack’s dimensions (height/diameter): 25/16 cm
Stuffsack’s volume: 5 l
Number of down chambers: 33