I use this one, and have bought a second one.
Motorcycle Helmet Wind Blocker - webBikeWorld
Both used on a Shoei TZR helmet. They add warmth and lesson the wind noise. Here in PA they can be worn almost year-round as they don't increase the heat much. Well worth the money when I commuted in cold weather. Fogging is borderline with it on. Different helmets may have varied results.
I had used one them on a different helmet first which caused it to fog too much (An HJC)
Anyway, I use this in cold weather in combination with a very thin, long neck gaiter which is tucked into my shirt neck, sticks out through the sealed jacket collar, and which is scrunched up around my neck. This also helps to seal the wind at the back of the helmet.