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Western Mountaineering says:
When you need a sleeping bag with the absolute minimum weight and packed volume, our Monolite could be the perfect solution. It is designed like the Flylite but without a hood to make it even more compressible and lightweight. Weighing less than a pound and stuffing down to about the size of your water bottle, it is a great choice for bike packing or adventure racing enthusiasts.
The 10 denier outer shell and lining materials are separated slightly by micro-baffles and it has an insulated top collar and draft tube behind a half length #3 coil zipper.
Rating & Materials
* Western Mountaineering state: 'We independently verify own temperature ratings through our own testing, customer feedback and design knowledge. Most of the items in our catalog we have been making for years, which means we have lots of prior knowledge from everyday consumers on what ratings are accurate. We have also EN tested our bags. In every case the EN rating is lower than our posted rating. This means our ratings are more conservative. We do this to ensure that almost everyone will be happy in our bags at the temperature we publish.'