I've been using various, including a Buff.
But, my fave is from SWRVE
. I bought a jacket from them about a year ago, and pretty-much live in it. On their mailing list, I saw they were doing masks. Bit the bullet and got some (you need to get quite a few for cheap shipping). Ordered at 6pm on a Friday. They arrived 2pm that following Monday. From LA. Luckily, it's my favourite mask. By a wide margin. I'd like to get a couple more.
But then, Barefoot has his own design. (Can you ping people in here? I forget. Does he still have his login?)