I just found something I am actually going to invest in. I'll buy at least one so I can figure out how to make them on my own in the future, but it's too genius to pass up.
This is a "polar" buff. I use buffs as insect shields, an extra layer of warmth, a hat or facemask when outdoors in cooler temperatures, but this buff adds another layer to that. One side of the buff is regular, lightweight synthetic buff material and the other side is thick, warm fleece. They're made into a buff tube, and sewn so that you can flip them around, and also make all sorts of things: a hat, balaclava, or facemask with a little practice (check out the video for an example of how).
Who else wants one?