Corner Bead is a piece of material where the name is derived from the function. Drywall corner bead is the material that "drywall hangers" and "drywall finishers" use to cover up a seam where two pieces of drywall sheets meet at the corner of the wall, or along the edge of an arch. Corner bead comes in two different styles: square and bullnose. Square, or 90 degree, corner bead is placed on a corner if the project calls for a corner that has a straight "clean" finish. Bullnose, or rounded, corner bead gives a corner a more rounded look and does not come to a point like square corner bead does. Both types of corner bead are used fairly regulary, and give corners an added finished quality. However, when using bullnose corner bead it is important to consider whether or not a base adapter (creates a square edge along the bottom base of the corner) needs to be used to account for any type of trim that may be running along the base of the wall.