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