This internal or mortise style latch assembly has a plastic body with a rotating steel latch. It installs into a slot or mortise in the edge of the sliding screen door. Mounting holes are 3-7/8 in. on center. The lever fits through the door frame and into the latch assembly. The latch hook rotates upwards to engage the keeper installed on the door jamb. For the keeper use Prime-line part A 127.