Rab describe the Alpha Flux jacket as “a new breed” of garment, and it’s certainly true that this defies easy classification. But it’s this very versatility which makes this special, and has earned it its place in the Outdoor 100.

Essentially it’s a mid-layer, but it looks great and in warmer weather it serves equally well as your outer jacket. Whether you’re hillwalking, fell-running, climbing, mountaineering or ski touring, this is a useful piece of kit to stuff in your rucksack. And because it packs down small and only weighs 330 grams, it won’t take up much space or slow you down either.

The main reason the Alpha Flux is so versatile is that it’s warm, but also boasts excellent wicking properties. The insulation is made of a fabric called Polartec Alpha, which was originally developed for the US Special Forces. This means the inside of the jacket looks like a thick shag pile carpet.

“The shag pile-style Polartec Alpha might feel like the interior of Austin Powers’ apartment, but this lining is actually a hugely effective insulator.”

Polartec Alpha might feel like the interior of Austin Powers’ apartment, but this lining is actually a hugely effective insulator, trapping warm air between the fibres. At the same time, it’s highly breathable, moving moisture efficiently through the fabric and away from your body.

This, combined with its hydrophobic properties, means it dries quickly too. Although this isn’t waterproof, if you get caught in a shower, the synthetic insulation will continue to perform well and keep you warm.