When it says Windstopper...
... it means windstopper. I landed in a small Cessna 206 just in from remote Alaska smack in the middle of a windstorm: 30MPH sustained winds, with up to 40MPH gusts. I yanked the drawcord tight at the hem, zipped up the collar and waited for the wind to punch through the jacket. Never happened. All of that wind, and none of it penetrated. Stayed warm, albeit it beat up, in the wind. Lots of products don't live up to the hype... this isn't one of them.