Brompton New York Merino Multitube - Grey Marl
One of the most simple yet versatile items you'll ever wear has to be the good ol' necktube.
Worn around the neck it'll keep you warm and comfortable no matter what the conditions are. Bring it up over your face to protect against icy blasts or swirling dust. Worn as a bandana it'll keep the sweat out of your eyes and your head nice and cool. In a mid grey, you won't have to worry about it clashing with your outfit.
Best of all, as the multitube is made from merino wool - it won't get stinky!