No actuation method. Due to our “opposing wing design” AMD still sells a large quantity of mine doors that are opened and closed manually. This can be done due to our design; the door actually uses the air pressure in the mine to assist with opening and closing the door. If an AMD doors wings are opened up 50%, the doors will remain in this position and not slam open or closed from the air pressure. This “balanced” design is the safest door design in the world.