An awesome skull bandana that'll cover your neck and mouth - and for under $5! Super cheap and quality too.
This will fit just about anyone, even if they have a huge head. If it doesn't fit because their head or neck is freakishly huge, get two and tie them together!
Actually you'd have to make some adjustments in that case because this is actually a tube that you slip over your head. It's not a "bandana" that you have to tie up. The cloth is very stretchy and will fit *most* adults.
Great for snow skiing, snowboarding or the like. Very cool under $1 product from Amazon!