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Helium 300 4 to -1°C Down Sleeping Bag

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Minimise your load on your next bush walk with a Helium 300 lightweight down sleeping bag. Outstanding warmth in an ultra compact package ideally suited to cool weather, three season camping in temperatures as low as -1°C.


Minimise your load on your next bush walk with a Helium 300 sleeping bag. Outstanding warmth in an ultra compact package ideally suited to cool weather, three season camping in temperatures as low as -1°C.

Ultralight shell fabric and high-loft down fill on the Helium bags mean higher performance for less weight. Durable 10 by 10 denier, 520 thread count Nylon weighing only 26g/m2 with a hot-rolled-cire treatment to prevent down leakage and increase durability. Premium 800+ loft white down fill with DWR Loft treatment adds greater resilience, higher loft and better warmth in damp conditions.



800+ loft water resistant down

This product is filled with Premium White Down with a loft rating of at least 800 cubic inches per ounce.

Mont's down is selected for it's high quality, purity and the fact that it is not live plucked.

Hydrophobic Epic Thread
Hydrophobic Thread

All Mont Sleeping Bags are sewn with hydrophobic Epic Thread. The silicon impregnated in this thread prevents moisture wicking along seams and into the bag, keeping down dryer and warmer.


Ultralight but durable 10 by 10 denier, 520 thread count Nylon weighing only 26g/m2. Finished with a hot-rolled cire treatment to prevent down leakage and increase durability.


Differential cut is the term used to describe the difference in circumference between the inner and outer shells. The differential cut prevents down compression and cold spots by reducing the chance of the inner shell compressing against the outer shell.

For a truly effective differential cut there should be a considerable difference in the circumference of the inner and outer shells.


The Radial Arc Baffle System is a significant design innovation that improves the thermal efficiency of a Mont Sleeping Bag.

Radial Arc Baffles curve naturally around your body rather than bending around your body. When a down baffle (chamber) is bent or distorted, ripples in the fabric occur which will compress down and create cold spots. The Radial Arc Baffle System reduces bending and distortion and increases loft and warmth.


Tuck stitching is a construction method that conceals the stitch inside the sleeping bag thereby protecting it from abrasion and snagging. This is in comparison to top stitched seams where each stitch is exposed. Tuck stitched seams are also more water resistant than top stitched seams, again because the seam is concealed internally.

Tuck stitching attaches the lock-knit baffle fabric to a small fold in the shell material. Tuck stitching joins three layers of fabric making for a much stronger seam than top stitching that only joins two.

Customer Reviews
5.0 Based on 2 Reviews
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    Rohan K.
    Hands down brilliant

    My team and I used these during the 550km, 7 day expedition adventure race: Godzone, in New Zealand. Conditions were damp and cool. In short these sleeping bags were brilliant. Though slightly bulkier than their synthetic equivalent, and about 70g heavier (not even 3 x AA batteries) these bags were easily more than twice as warm. The high loft down proved to be significantly better than previous down bags I've used in the past. The pertex outer - though it feels (and looks) worryingly thin - held up to the rough and tumble of shoes inside sleeping bags, and the rough hasty packing that goes with racing. The DWR treatment was suprisingly effective. Though the down was begining to clump at the end of our race, its insulation properties had been admirably preserved throughout. Despite camping in heavy fog and light rain with three people in a single skin tent with water dripping off the walls, the bags held their own. Temperatures hovered around 0 and 5 degrees, which was never a problem - even for our cold-blooded 'racing wife'. At 6 feet tall the cut was generous enough to accomodate my length, and roomy enough to allow for some movement. The hood was perfectly sized, and closed nicely around the face to eliminate hot air loss, without covering our mouths. The simplicity of two draw cords using the one toggle was east yo use, and the removal of all those little additions such as a key pouch, neck draft tube, zipper garages and compression stuff sac were all appreciated when the sleeping bag went on our backs. Being able to open the bag right up like a light weight duvet was handy, though we appreciate it added perhaps 50g or more. Very hard to criticize this bag. It's not a bag with bells and whistles - but thats exactly why it's so light. Possibly our only criticism would be that the stuff sac is a perculiar shape. A longer more cylindircal shape might have been nicer. We can definitely reccomend these bags as hands-down brilliant. Perfect for the person that wants the almost lightest sleeping bag on the market, but still has the features to make it comfortable for spring, summer and autum. Well done Mont

    Andrew G.
    Excellent, well made bag.

    I bought the Helium 300 about 6 weeks ago as a lightweight option to my 30 year old bags that are nearly 3 times the weight. I have had an opportunity to use the 300 twice since. The first time was in a camping cave, sleeping in the open and it performed very well. I always use a silk liner in my bags and slept comfortably but it was a still, mild night, so hard to make an assessment on how it performed when the temperatures drops. Well that opportunity came with the next use where below zero temperatures were predicted. Given the rating of the bag I thought it might struggle in these conditions with just a silk liner so I purchased a thermolite liner to give some extra warmth. We were in a tent this time and it ended up being a very cold night, probably down to about -3 C and the bag performed well given it was considerably colder than the comfort level of 4 C and even below the lower limit of -1 C. I slept well enough, but it would not have wanted to get much colder. I am a warm sleeper though, so I think you'd need the Helium 450 or 600 if you are a cold sleeper and you'll be in conditions that fall below the comfort level rating of the 300. Overall, very happy with the bag so far and I'll probably end up purchasing the Helium 450 or 600 for use when it looks like below zero temperatures are on the cards.

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