At a glance Plusses: Attractive design, good warmth for weight, designed for active use. Minuses: Soft outer frays and snags easily. Technical, it’s a relatively niche layer.Features: The Alpha Flux is a technical, lightly insulated hooded fleece with a slim cut and flattering appearance. It can be worn as a mid-layer or an outer layer in warmer conditions. The jacket has a super-soft breathable shell with stretch side panels, cuffs and thumb loops. The inside is lined with Polartec Alpha Direct 90 fleece insulation. The fleece feels more like sheep’s wool and is pleasant against the skin. The front zipper is fully baffled and has a chin guard. When zipped up with the stretchable hood on, the jacket sits snug and tight like an extra skin. Fit: It has a slim fit, active cut which makes it best suited as a mid-layer worn under a shell, or a downie on a winter trip. The stretch cuff and thumb loops make it a comfortable fit even for those with very long arms. I wore it on a range of activities and it performed well across the board, but it really shone while cycling and skiing, where the thumb loops would prevent the sleeve riding up my arms. Comfort: The Alpha Direct insulation is surprisingly comfortable against the bare skin and provides impressive warmth for weight (it weight 330g -m / 280g -w). The soft outer and generous stretch panels make it a comfortable active layer to move in, while the breathable outer helps to keep moisture levels down. In use: Where the Alpha Flux really falls over is durability. I wore it on a walk in the bush and while climbing and it immediately started to snag and fray. This won’t be a problem if you intend to use the jacket as a mid-layer, but after only a couple of uses the jacket was showing signs of wear. Otherwise, I found it to be a useful layer that packs down well. I wore it tramping, climbing and running, among other activities, and enjoyed the combination of warmth, comfort, looks and the freedom of movement it offers. Value: Being a technical layer that features new fabrics and a slim profile, the Alpha Flux is priced above often considerably warmer thermal layers such as a polar fleece or down jacket. However, it is a better active layer and still provides respectable insulation for hanging out at camp on warmer trips. Verdict: A cosy, stylish and technical mid-layer with a slim fit that is let down somewhat by its propensity to fray easily.