Weight-weenies: this is your gilet. The Optik is described as ultra-light and it is. It's easily the lightest gilet here and it packs down very small. There's no mesh on the back, just thin polyester fabric all over. But it's thin enough that breathability isn't an issue.
It's a better windbreak than its weight would suggest, too, and also puts up some resistance to showers. It's cut fairly close with a tightly elasticated waist. The collar and arm holes could be closer and tighter, though. At speed, wind gets in at the shoulders and makes the lightweight material flap noisily. The front zip is lefthanded, which is odd but perhaps for the best: it forces you to take more care, so you're less likely to snag the storm flap with the fine zip. There's a small zipped pocket on the back, which would take a phone and a couple of tiny reflective logos; although something bigger would be better.