 800-fill Expedition  800-fill #0  800-fill #1 Spiral  800-fill #3 Spiral |
Mont Bell Down Sleeping BagsMont Bell sleeping bags are all about getting the best warmth for weight ratios. Traditionally, the best way of achieving lighter (and more compact) bags has been to use higher quality down which lofts more - you need less 800-fill down than 550-fill down to achieve the same warmth. But now clever shell fabrics are making a major difference. Mont Bell use a nylon fabric called Ballistic Airlight. It is special in that it is stronger than traditional nylon twice its weight, hence it can be made lighter.
Now we get to where things get truly wicked. Mont Bell sleeping bags stretch - heaps. An extra benefit of Ballistic Airlight is that the nylon has been hollowed and flattened, so the fibres lie on top of one another, preventing down from escaping whereas down leaks between the fibres of traditional nylon.
Specfications I hate using temperature ratings for sleeping bags because thay are so objective and many factors determine how warm you will feel in a given sleeping bag on a given night (recommended reading). The temperatures are listed as guidelines with the "comfort temperature" suggesting a good night's sleep and "usable temperature" suggesting a managable sleep if wearing warm clothing. On the other hand, simply looking at how much down (in grams) and its lofting power (fill-power) can be equally misleading owing to all the design considerations described above. Regular length versions suit anyone 183 cm (6 ft) or shorter. |
Ultralight sleeping bag cover |
Mont Bell Ultralight Sleeping Bag CoverThis is an alternative to a full-on bivy bag. Not everyone wants or needs the full thing. This cover is for those who are simply concerned about a leaky tent, dripping snowcave or dew/light rain. It can also be used for bivying in worse weather if the head is under shelter (e.g., in a small snow cave) and the body is exposed to the elements. The waterproof/breathable bag weighs only 235 grams. Having a lightweight 'bivy bag' also means that the weight of the material isn't preventing your down sleeping bag from fully lofting. |
Inflatable pillow A$45 (70g) |
Mont Bell PillowThe inflatable pillow is one of the greatest inventions for mountaineers. It is so light (70g) and small you will never leave it behind no matter how light you are travelling. It is even contoured for the head. |
Other than the obvious weight savings there are benefits for the down.
Lighter nylon compresses the down less. Furthermore, it is okay to use more nylon to create smaller baffles and baffles with curved surfaces, which again permit down to keep its loft. Hence the 800-fill down in Mont Bell bags behaves as even higher quality down. 
Finally, we turn our attention to the water resistance of the nylon. Water resistant shells always sound like a good idea but the issue in the past has been their weight and bulk. They defeated the efforts of making light, compact bags in the first place. What was really needed was a quality DWR repellent, but none existed. (DWR coatings weigh practically nothing and are the coating on the outside of your expensive rain jacket that beads raindrops but wears off pretty quick). Now, however, there is Polkatex which is the very best (and very expensive) DWR - keeping 90% of its repellency after 100 washes (that's a technical testing method). This is what Mont Bell use for their performance bags. 
