Abstract: A drywall finishing system for finishing 1) normal inside and outside corners of any angle, 2) stub wall or closet corners, 3) window wrap corners, and 4) L-metal for window sills and areas where drywall ends against some other surface like brick. The finishing system comprises a preformed trim piece comprising a semi-rigid member that is relatively thick in the center and tapers laterally to a thin edge. A layer of paper is bonded to the inside surface of the semi-rigid member for receiving joint compound to continuously bond the trim piece to the dry wall. A layer of finishing material is bonded to the exterior surface of the semi-rigid member. To install one of the pieces, it is selected from stock and cut to length. A flat coat of mud is applied to both sides of an exterior or interior angle, and the trim piece is placed over the mud and smoothed into place. Since it is preformed, the piece makes a straight line at the required angle.