This mortise lock is constructed of steel components with rounded faceplate ends. It features an adjustable, spring-loaded hook latch projection, and it can be used on sliding patio doors constructed of wood, aluminum and vinyl. This lock works with mortise style, surface-mounted patio door handle sets with 45 deg. angled keyway positions when in the locked position. The mounting hole centres of this lock measures 3-11/16 inch from center to center, and the rear housing corners are square. This mortise lock is used by many patio door manufacturers.