The Montane Icarus is a warm, functional jacket at a good price, but quite heavy.

Montane says it’s ideal for mountain walking in mixed conditions. It would have to be very cold before I could walk far in it without overheating. In cool windy spring weather, it was warm enough for me to be comfortable standing still, just over a T-shirt. That’s because the fit is on the small side. To wear it over a thin fleece I’d need the XL size. I can’t imagine doing any fast-paced activities in the jacket anyway, except maybe in a blizzard. 

The Montane Icarus fill mimics down and is held in micro baffles. It feels very soft, and the jacket is comfy. The hood isn’t adjustable but is close-fitting. It fits under a climbing helmet. The bottom of the handwarmer pockets is cut off by a hipbelt but still accessible. The chest pocket is too small for a map but takes a smartphone or GPS unit.

As a winter jacket for rest stop/camp use and maybe walking in the worst conditions, it would be ok. However, there are alternatives that weigh less and pack down smaller. 

See how the Icarus compares to other synthetic jackets in our guide to The best synthetic insulated jackets