It is an Avery Neck Gaiter. Here is how its used.
It fits over your head then tightens with a bungee cord to keep the wind out. Obviously this isn't the cutest look going. More of a "my car stalled on the highway and I am trying to change my tire without my ears falling off" look. I've been thinking about "borrowing" the idea and making my own non-camo version. So I tried it out this weekend using a felted wool sweater with fleece lining. Here is my result. It's missing the bungee cord, but you get the idea.
It was really easy to do and probably took me about 2 hours. Will be much quicker next time I'm sure. I think I will be adjusting my Christmas in Progress list and might whip up a couple more of these for my February goal. The neck warmer pictured will have to be for a guy. It turned out pretty big and practically covers my whole head. The woman's version will be a bit shorter. I think I might try to knit something similar as well and make it a little more attractive.
If you also live in a frozen tundra and would like to try and preserve whatever frozen bits you have left on your face, I would be happy to share some more detailed instructions on these, just let me know. Or better yet, just wing it and make up your own variation and let me know how it goes!!