Seirus Innovation Unisex Neofleece Combo Scarf

how can i know my size?( i wear medium size helmet.) Thank you!

can it fit an 8 yr old

Will this warm the air being breathed in? I'm wondering if the holes are big and allow cold air in when breathing through nose or mouth.

does the mask keep my face warm? I'm looking for mask that i can wear it between my class do you think this mask work for my needed? Thank you!