At Ultralight Outdoor Gear we're always looking for the lightest weight product that will do the job, that's our bottom line, but we also have a few other lines we don't like to cross - our products need to be robust, packable and have a reasonable life expectancy.
I was pretty excited when RAB produced the Zero G and managed to get one in time for my three week trip to the Himalayas. When considering insulation for a high altitude trek I always assume its going to get to around 0C as soon as the sun goes down and stay there until it comes up the next day. While there was a wide variation in nighttime temperatures we recorded 2C on a number of cold mornings.
Insulation is therefore vital and I tend to rely on a very lightweight synthetic piece for during the day and a down jacket for evenings and mornings. I don't find that I need a huge down jacket, something around the 400gram mark keeps me warm enough.
The Zero G is perfect for this application - for a total weight of 352grams (XL) it packs in 130grams of the highest possible quality down, that's an amazing ratio for a hooded jacket with pockets (and everything!), its lighter than the Yeti Virtue jacket which only has 104grams of down, and the Haglofs Essens III with 103 grams..etc.. I could go on but you can compare them yourself, its our lightest jacket with this amount of down.
Then there's the quality of the down - 1000Fill Power, we don't have many garments using this quality of down because the price of the down is so high and stocks are hard to come by, however the combination of the down quality and amount in the jacket make it very warm indeed considering its overall weight. I was warm at 2C with just a thin Power Dry baselayer underneath the jacket.
The Pertex Quantum fabric is of course very thin being 7 denier but it doesn't feel weak, the danger is snagging on anything sharp with this weight of fabric so some care is needed, but in normal use it will be fine. I abused mine a bit packing it in and out of my rucksack on a daily basis but it stood up to this very well.
Feature-wise there's nothing missing, there's a tab to roll away the hood and one to adjust its volume, it even has a wired peak, although this is very lightweight with limited functionality. The main zip has an internal baffle and there are two handwarmer pockets. The hem is a slight compromise, there's no drawcord, this has been replaced by elastication, but this seems to be set at the right tension. I really liked the cuffs, which have a knitted section for ultralight comfort.
Like all jackets this light there were a few occasions where down poked through to the outside, the key thing here is to carefully pull the filaments back into the jacket and not lose them - which I did.