Mont Helium 680 sleeping bag: Tested

By Mattie Gould 12 June 2024
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Camping in the cold alpine backcountry means your sleeping bag needs to be warm, comfortable and robust. We doss down in the Mont 680 to see if it fits that bill.

Whenever you’re hiking, biking or skiing into the backcountry for a night or two, it’s always a fine balancing act of packing gear that will keep you warm and safe that’s also light enough to carry along for the ride. If you’re camping out over winter, then the warmth of your gear is about more than just staying comfortable, it’s about keeping you alive. Enter the Mont Helium 680, a four-season sleeping bag from the iconic Aussie outdoor brand.

A reliable, warm sleeping bag is an absolute must when exploring the outdoors in colder conditions, whether it’s in our alpine country, or southwest Tasmania.

Mont’s Helium range aims to maximise the warmth to weight ratio of your sleeping bag, which makes it an ideal place to start your search for a warm and lightweight winter sleeping bag. As most of my winter camping takes place around Canberra and nearby Kosciuszko National Park, I opted for the warmest bag in the range, the Mont Helium 680.


The Helium 680 is a lightweight sleeping bag filled with 800+ loft premium RDS white duck down. It has a lower temperature rating of -6 to -12 degrees Celsius, making it ideal for winter campouts. Prioritising packability, the sleeping bag packs down to a relatively small 16x33cm (smaller if really cinched into the stuff sack) and weighs around 1.1kg.

The mummy-shaped bag still provides decent interior space without sacrificing warmth-inducing features, such as its contoured hood.

While the bags are a mummy shape, the internal shoulder room is a generous 160cm circumference, tapering down to 115.5cm circumference in the foot box (in the standard size bag). Further warmth and comfort inducing features include the box foot area at the bottom of the bag, a contoured hood, vertical baffles on the torso and a down filled 3D draft tube along the zipper, to name a few. 

In the field

Having previously tested out the Mont Zero Superlight sleeping bag, I was already familiar with the quality to be found in Mont sleeping bags and the 680 was no exception. The first thing I noticed on unpacking the 680 was how much larger it is than the Zero. It still packs away into a small enough package to fit in a saddlebag, or at the bottom of a hiking pack, but once released from the stuff sack, it lofts and expands into a reassuringly puffy sleeping bag.

For such a warm bag, the Helium 680 still packs down impressively small, using the supplied compression sack.

As mentioned above, the ample shoulder room and foot box give the sleeping bag a roomy, comfortable feel – even when wearing extra layers – and it doesn’t feel as restrictive as other mummy bags. The hood really was warm, and I found that I used the elasticated cinch to shrink the opening smaller and help trap in all that hot air my body was generating.  

The Mont compression sack that’s included with the sleeping bag does a great job at compressing the bag, but if you’re planning on using this bag on winter bikepacking adventures, you might want to find a compression bag that creates a longer narrower package as the wider diameter of the included stuff sack makes it an unsuitable shape for a bikepacking saddlebag. However, I did find that I was able to squish the bag into the saddle bag using a normal dry bag and the compression of the saddlebag itself. This is, of course, not a problem when taking the Helium 680 hiking as it easily fits inside a hiking pack.

The final word on the Mont Helium 680

Mont is renowned for producing high quality camping gear and I have been super impressed with my experiences with the Helium range. With the Helium 680 the company has struck a terrific balance between lightweight packability, and a seriously warm sleeping bag and it’s been reassuring to know that I’ve got a warm night ahead of me no matter what the Australian winter throws at me.

This four-season sleeping bag is made with durability in mind, and is loaded with innovative features.

RRP: $999.95 See Mont for more info on the entire Helium sleeping bag range.