In reply to PN82:
That looks interesting, you may have just done me a big favour. I was on the verge of buying something less warm at 3x the price, e.g. the new Haglöfs belay jacket.
The things I was looking at have 100g filling, around 400g total weight, and I was thinking in terms of wearing them as a second warm layer over a lighter insulated jacket (Atom LT). A full-on standalone belay jacket might be overkill for that, and is considerably heavier. Otoh at the pice I can try it and don't have much to lose.
But sizing? Do they size, like the DAS, on the basis that an "L" belay jacket needs to be easy to throw over an "L" fleece and shell, or would it be wiser to go up to XL?