A Büf (BOO-ph) is a black silk, velvet, fleece
hat woven in a form similar to that of a beanie (but worn in a
way that covers the wearer's ears, forehead, and neck) with iron studs woven across the surface. A Büf (Bæf, for plural) is traditionally worn by followers of the Korrui religion during the span of
time from Krampus to Luna Flame.