Cumulus X-Lite 300

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The Cumulus X-Lite 300 is, for its respective fill weight, the lightest sleeping bag  in the world. Perfect for mountain marathons, minimalist alpine ascents and fast and light backpacking. 

Simplicity and lightness – these two words best describe the Cumulus X-lite sleeping bag series. Thanks to their functional, minimalistic design these sleeping bags are the lightest in the world. The Toray Airtastic (19 g/m2) fabric and 900 cuin goose down filling of the highest quality guarantee that the weight of the sleeping bag will be barely noticeable in your pack. 


Designed and built in Poland, Cumulus draw on 30 years of experience and know-how in down and textile manufacture to provide some of THE best sleeping bags on the market. At the vanguard of sleeping bag construction techniques and design innovation, Cumulus offer as many as five methods of chamber construction, each developed to offer its own unique benefits [Cumulus Down Sleeping Bag Construction article]. All bags use sustainably sourced Polish goose or duck down, high-grade face and liner fabrics from Pertex, YKK zippers and, unlike most other sleeping bag brands, are entirely constructed in the EU.


Temperature ratings are used to indicate a bags performance and help you decide between models. However, they are subjective and can be greatly affected by factors such as what you're happy to wear (clothing wise) in conjunction with the bag, your health and metabolism, how much you have had to eat or drink, humidity and altitude, the type of shelter used and whether you are using a suitable insulating mat.

As a guide, the "Comfort" rating indicates the range at which a woman gets a comfortable night’s sleep, the "Limit of Comfort" rating indicates the range at which a man gets a comfortable night’s sleep and the "Extreme" rating indicates a range at which a woman is protected from hypothermia. The Extreme rating is basically a survival rating and it is not advisable to rely on this for general use.

More Help? For further assistance on choosing your down sleeping bag, please view this article explaining fill power, the pros and cons of down over synthetic insulation and more info on caring for your bag available to view here: A Guide to Down Sleeping Bags.


  • Fabric: Toray Airtastic™ DWR, 19 g/m²
  • Filling: Polish goose down, 900 cuin
  • Construction: trapezoid chambers
  • Independently filled top and bottom of the sleeping bag
  • 2/3 YKK zip with two self-locking sliders
  • The zipper can be opened at the bottom for better ventilation
  • Shark-fin footbox construction
  • 3D, adjustable hood with a draw cord, a lock and a tape
  • Additional, large mesh bag to store your sleeping bag at home


  • Total weight: 465 g
  • Down weigth: 300 g
  • Weight of unfilled sleeping bag: 165 g
  • Comfort temperature: 2 ˚C
  • Limit temperature: -4˚C
  • Extreme temperature: -20 ˚C
  • Maximum user height: 185 cm
  • Length: 202 cm Width (top/bottom): 77/1 cm
  • Stuffsack’s dimensions (height/diameter): 20/15 cm
  • Stuffsack’s volume: 4,2 l
  • Number of down chambers: 30

10 Year Warranty
Made in the E.U.

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      IAN W.
      United Kingdom United Kingdom

      X-Lite 300

      I've had quite a few sleeping bags over the years, mainly down filled, but this one is just amazing, especially in the loft (and warmth) considering how small it compacts to and its super low weight. The shape is quite slim and may not suit everyone, but for a skinny guy like me its perfect.


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