This is basically a polartec fleece. It is not windproof, at all, and a little bit longer than most cycling jackets which means it hangs below most shells that would make it windproof. It’s not really heavy, but not light or packable. So you can’t really use it in the cold whether if you’re moving at any speed without a shell, and don’t want to wear it when it gets warm enough that wind doesn’t mater, because its to much. So, I really don’t know when this is good. Sizing probably is true to size but there is very little stretch, and it pulled against the back of my shoulders, so i had to size up. I would have given it one star, but gave it two because maybe I’m missing something.