The Fuse Uno is touted as a technological breakthrough and a new way of making wet weather gear.

It’s part of TNF’s FuseForm range, which includes garments made from a single piece of fabric folded into a jacket. The benefits include fewer seams, better water tightness and lighter weight – and greater durability. At 351g, there are few lighter three-layer jackets on the market.

I tested it in alpine conditions and in three days of constant rain. In Tongariro National Park, the jacket performed well – it kept the rain out, the generous hood accommodated my helmet and I had good freedom of movement. On Stewart Island, it protected me from the sometimes horizontal rain, but while HyVent Alpha fabric is highly breathable, in the humidity of the bush I produced far more sweat than it could deal with. I guess you might expect that if you take an alpine jacket into the bush.

There are challenges to creating a jacket from a single pattern. While there are two pack-friendly water-resistant pockets large enough to hold scroggin and map, the two triangular-shaped chest pockets are far too small to hold anything of value. The hood has no method of adjustment because the current construction technique does not allow drawcords to be added. If you’re wearing a helmet, it’s barely OK,  but without one my head was lost and strong winds would blow the hood off. Without pitzips, there’s no way to adequately regulate body temperature other than opening the main zip.

TNF should be applauded for its innovation and I’m sure future iterations of this jacket will improve on the concept, but for an alpine jacket, the Fuse Uno has its limitations – a usable hood key among them.