The HyperTherm is a fascinating piece at the lighter end of the spectrum in this roundup – insulation with the emphasis on ‘active’. It feels wafer thin and feathery light, but gives a surprising amount of warmth given how diaphanous it is. Insulation is provided by the synthetic Hydroloft inner, sandwiched in two different thicknesses of ripstop. That means the jacket is reversible, one side being more air permeable than the other. I’m usually a bit dubious about such claims but the jacket really does seem to have two settings – more and less warm. Hem, sleeves and hood are all lightly elasticated and there are two zipped handwarmer pockets. The fit is relaxed and while it isn’t waterproof, it seems to shrug off damp, drizzle and condensation easily. It also packs down to practically nothing and is slippery to the touch, which means it sits really well under a shell. While I don’t know yet how it will fare on the durability stakes, it’s a really impressive package, and crazy light at 233g.
VERDICT: Very flexible and light active insulation layer.
BEST FOR: Backpacking, running, those who run warm but need something just in case.
Review by David Lintern @