The lightest and most compressible bag in my test, the Hyperion features 900 fill power hydrophobic down treated with Nikwax, with the down ‘top loaded’ onto the front of the bag – the logic being that ‘loft’ is what keeps you warm, and the down under you is compressed. That does mean it’s designed to be used with a mat – and it’s worth bearing that in mind for summer as well, when you might be tempted to save a bit of weight and only carry a half mat, or something thin. The zip is half length and the fit is very mummy like but isn’t constrictive around the arms and shoulders. The zip baffle is a little economic but works, but there’s no shoulder baffle. The brand reckon the comfort level is 0 and the limit is -6 deg C, which feels about right to me. I loved the 600g weight, the super compressibility and with a full length mat I was not cold even at a couple of frosty camps.
► Verdict: Ultra lightweight, super compact and lots of cosy down on top.
► Best for: 2 to 3 seasons, where weight is an issue.
Review by David Lintern @davidjlintern