VERY lightweight and pretty thin. I was concerned it would not have the balls at first, but I have been very impressed! The first couple of 'wears' were over a t-shirt, under a shell at 0-2 degrees early morning while shifting some tools and gear at work - and I was toasty, too toasty! Casually (read 'slowly', Christmas market stalls were still out...) wandering round town last night, again only over a t-shirt and similar temperature, again I was comfortable. If I had been wearing another layer under and gloves and hat, I would have been cosy. You may be thinking ''its 700 fill, what do you expect'', but, this jacket is so light and tiny you could be forgiven for mistaking it for a 'summer' jacket. I have little doubt that doing any amount of exertion such as walking, climbing, riding, whatever, coupled with suitable accessories (gloves etc), this jacket will deliver well beyond its designated 'layer' duties! The pack down size is pretty tiny by the way. It also looks pretty 70's retro cool with jeans, and is a nice alternative to the fat puffa jacket brigade. The colours in the photos are calmer in the flesh; I got the blaze red and it is far easier on the eye than website pictures suggest. Get one... I love it!
Darren, Hertfordshire