A metal throat guard used by medieval soldiers. The word Bevour/Bevor loosly translates to "Dribble box", as the heat of the breath on the cold metal would cause condensation near the mouth. Comprised of a piece of metal that rested over the neck and onto the chest, with two or three pieces of metal that went up to the nose of the solder, articulating so it could fall down to the throat, mainly for breathing (known as a falling bevor). Also just simply metal all the way up to the nose, without articulation. Some would have a locking pin at the side, to prevent the articulations from dropping during battle.
The soldier flicked his bevor up, dropping the visor on his Sallet to lock them in place.