Adjustable from top edge of door Advances in design provide low operating temperatures, making this Shear Lock suitable for use in the growing demand for concealed locks in wood frames. Innovative gravity force design provides for movement of both lock and armature to overcome gaps of up to 1/4??? Requires filtered, regulated power supply Built-in Automatic Relock Switch Adjustable time delay on relock, 0-30 seconds Low temperature operation Microprocessor controlled