In reply to mh554:
That's a very different jacket to the one in the OP, it's basically a standard Rab Generator with a hood so much more 'lightweight'.
The one the OP is looking at is almost identical to the Rab Generator Alpine, with some minor differences. It's slightly lighter, lining certainly and I think outer are different, zip is different but in terms of use it makes little difference
I have a Rab Generator Belay in orange (but in the style of the red one on Cotswold!) and I really like it, I use it as a throw over all layers belay jacket in winter. I was tempted by a Generator Alpine but it was a little heavier than I wanted so when I found this it was ideal. I believe it is a special/prototype/concept or whatever and was never part of Rab's 'official' line up hence the lack of any details online.
I can weigh mine tonight if you would like some more info whilst deciding whether or not to buy
