Buff is a commercial version of the traditional British Army neck tube, called a headover. It is quote long so you can double it up or use it single layer.
You can wear it as a neck loop, an ear warmer, a neck/ear warmer, a neck/ear/head warmer. I sometimes use 2, once for neck and one for head and ears.
I have a polyester and a merino wool version, the
merino one is better.