Andersen Frenchwood Hinged Patio Door Lock Actuator. Used with the 2579512 and 2579771 3 point locks.
Square Shaft is 13/16 inches long,
overall length 1-1/8 inches. This is the only one made for the Andersen Door

This lock actuator is located underneath the inside escutcheon plate. It is held into place with 2 screws and a limiting plate. When the dead bolt knob on the escutcheon plate is turned it rotates the actuator which locks the dead bolt.

NOTE:
KML by Andersen Door has a longer lock Actuator # 9050896 made for the custom 2-1/4 inch thick doors by KML