Hmmm. Not convinced. Back when Karrimor weren’t awful, I bought a cycling jacket which looked exactly similar to this. It made similar claims in terms of windproof-ness.
It hung off me like a wet rag – just far too thin to be useful. That said, fabrics have come a looong way in the intervening years – I just know that very thin jackets make me look skeletal and suspect this would be no different.
Also (forgive me), what’s it for? I have a Gore Paclite fluo jacket which fits in a pocket. Fairly breathable, windproof and completely waterproof. Covers more bases in terms of the weather changing.
I guess it’s OK for windy days where you might go up and down a bit and want to regulate your temperature…