The Cumulus Quantum 350 is an extremely lightweight bag at just 702g plus an extra 20g for the stuffsack. It also packs down very small and appears to be ideal for anyone wishing to minimise their camping kit. The bag uses a trapezoid construction, so the seams are less likely to produce cold spots, which again is ideal for efficient and comfortable camping. There’s also a long side zip, extending all the way to the foot, unlike many bags, which stop at the calf area. This zip allows good venting of the foot area, and is a real benefit in warm weather. Behind the Cumulus Quantum 350’s zip there’s a baffle to prevent cold spots, but this isn’t as well-insulated as some other bags. I also found that the zip tended to snag on this baffle more easily than some others and this appears to be because there’s no wide stiffening strip behind the zip, a feature often provided to prevent this in other bags. There’s a small baffle around the shoulder but this lacks an adjuster cord and is, like other parts of this bag, less well-insulated than some others. There is a drawcord around the hood, but this isn’t quite as cosy as other bags either. Overall the Cumulus Quantum 350 just lacks some of the insulating ability of other designs.
Weight (with stuffsack) 702g (722g)
Length x shoulder width 200x77cm
Packed size 25x16cm
Outer fabric Pertex
Inner fabric Pertex
Insulation 96% down, 870 fill power
Comfort -6 deg C
Lower comfort limit no information provided
The Cumulus Quantum 350 doesn’t seem to be as well-insulated or as warm as other bags in this test, so while it’s very light and a good price, it isn’t the cosiest option.
Review by Graham Thompson
Published in Trail magazine June 2014
Lightweight fans note: the Cumulus Prime 700 offers an extremely impressive weight rating of 1210g and an equally attractive lower comfort rating of -18 deg C. If these numbers leave you cold, then holding the Prime 700 in your hands certainly won’t. It’s a staggeringly light piece of kit, yet it hasn’t sacrificed noticeable levels of comfort or performance to achieve it. The shoulder baffle drawcord and hood drawcord are well-placed and easy to use (including a well-placed Velcro patch to further secure your body space against the cold), while the hood is effective and comfy despite its relatively modest volume. The side zip action is positive and slick, and the Pertex inner is a soft cocoon to spend eight hours within. The foot room is relatively compact, and the storage and stuffsacks are the most basic here; however, they fit well within the lightweight mould. It also offers no waterproofing, so it will need to be kept protected from moisture and condensation if its considerable lower comfort rating is to be met. Overall, the Cumulus Prime 700 is an effectively minimalist and attractive sleeping bag.
Outer fabric Pertex Ripstop Microlight
Inner fabric Pertex Ripstop Microlight
Insulation 870 fill Polish white goose down
Sizes one size
Compressed pack size 17x36cm
Lower comfort rating -18 deg C
The Cumulus Prime 700 was the best lightweight down sleeping bag in our test.
Review by Dan Aspel
First published in Trail magazine March 2013
The Cumulus Ultralight 350 has a stripped-down ‘fast and light design’ that’s aimed at reducing pack weight and bulk. The commonly used trapezoidal baffle design is obvious on this model as the external stitch lines show the alternating narrow and wide faces of the baffles down the length of the bag. There is a full-length double-ended zip with an internal baffle featuring anti-snagging detailing and an external Velcro securing tab. The hood is quite a basic design and when cinched in it bunches up around your face a little. There’s no internal shoulder baffle so heat loss will be controlled by the hood adjustment, thus as with all the bags in the test it’s worth trying one out in the shop to see if the features suit you. The fit is slim on the Ultralight, especially in the leg area, where I found very little movement was possible. However the foot box was such that my feet had plenty of room and the down wasn’t compressed by movement, as was the case around my knees especially. The Ultralight has hanging loops and comes with a stuffsack and storage sack.
Weight (bag only) 804g
Size (length x shoulder width x foot width) 197x41x72cm
Packed size 12x27cm
Outer fabric Pertex Microlight
Inner fabric Pertex Microlight
Insulation 680 Polish goose down
Construction trapezoidal baffles
Comfort temperature rating n/a
Lower comfort limit -3 deg C
Extreme temperature rating n/a
The Cumulus Ultralight 350 is a very well-priced and warm sleeping bag thanks to its -3 deg C temp rating. Its basic design and slim fit will suit fast and light users with a relatively smaller frame; but at 804g it’s not the lightest option.
Review by Peter Macfarlane
First published in Trail magazine June 2012
Quantum bags are the lightest in the Cumulus range and they are designed to offer a superb warmth-to-weight ratio. So they use the best down available and combine this with superlight fabrics. To save a little more weight those in the Quantum range are slightly shorter and narrower than other Cumulus sleeping bags.
The Cumulus Quantum 350 is designed to optimise performance for weight, so it makes use of a trapezoidal construction. This is like a box wall construction with sloping sides to each box and it results in a bag that is warmer than box wall as cold spots are reduced between each box of insulation. This is also a lighter construction method than V-shaped boxes. The down is also top-quality, being 870 fill power Polish goose down. These features are combined with Pertex Microlight fabrics that weigh in at only 50g/m2 and Pertex Quantum, which weighs 32g/m2. The bag is also made with a differential cut so the top of the bag has extra room to allow the insulation to ‘loft’ in the top of the bag.
To save a little weight the Quantum range of bags are 217cm long, rather than the usual 220cm. Also they are 75cm wide at the shoulder when some bags are 80cm wide. All this adds up to make this bag extremely light at just 732g, plus
18g for the stuffsack.
On the hill
The Cumulus Quantum 350 packs down amazing small, making it ideal for light backpacking trips. Pull the bag from the stuffsack and it instantly feels soft, while the down soon lofts to make this feel very cosy. There is a good, well-filled zip baffle down the length of the side zip. I did snag the zip a few times though. There is a shoulder baffle on the front of the bag, but this does not extend around the back as most shoulder baffles do and it does not have any drawcord adjustment. The hood fit was okay, but others are better. Overall I did not think the head and shoulder area was as good as other bags. The shorter length of the bag was not a major problem for my 5ft 11½in frame, but I did notice that the width was a little tight, which resulted in compressed insulation at my elbows. Of course those with a slimmer build than me will find the width ideal.
In the lab
At 9.3TOG / -6.5 deg C the results of our lab test closely matched the temperature rating of the Cumulus Quantum 350.
Outer fabric Pertex Quantum
Inner fabric Pertex Quantum
Fill weight 350g of 96/4 white Polish goose down
Fill power 870
Lower comfort temp rating -6 deg C
Trail temp rating -6.5 deg C
Packed size 24x15cm; 18x15cm compressed
Weight bag 732g; stuffsack 18g
Made in Poland
Stores across UK 13
Stockist details tel. (0161) 929 1782; www.cumulus-sleepingbags.co.uk
The weight and packed size of the Cumulus Quantum 350 are superb. However, the zip snagged more easily than others; hood and shoulder baffle design not as good as other heavier bags. Overall, it’s great for lightweight backpacking but other bags have enhanced performance
Review by Graham Thompson
First published in Trail magazine Spring 2010
The Mysterious Traveller is another 3-sesaon down sleeping bag that sports a clean and simple design. It’s made from Pertex Microlight inside and out to give a good strength-to-weight ratio. The bag is also designed using trapezoid baffles which, although slightly more complex to manufacture, do give better long-term insulation. All this quality construction is provided at a reasonable price and weight. You also get the usual list of features including a neck baffle that seals with Velcro and draws in to reduce draughts, and a baffle along side the zip. To complete a very satisfactory picture, the Mysterious Traveller has been manufactured here in the EU. But although not the hardest bag to pack, the stuffsack is small, and its lightweight fabric may allow the seams to stretch under pressure. A larger stuffsack and a slightly tougher fabric and stitching would have been an improvement. The zip also snags badly when used.
Outer fabric: Pertex Microlight
Inner fabric: Pertex Microlight
Insulation: 500g of Polish goose down 680+ fill power
Packed size: 27x15cm
Made in: Poland
Stores in the UK: 13
Verdict: Top-quality fabric, good design and warm results; but the stuffsack could be bigger and the fabrics could be tougher.