Abstract: A transfer port system between two sterile environments having docked and undocked positions which is made up of two door frames connected to the environments and two doors connected to the two door frames. When the sterile environments are in the docked position the door frames of the two doors are juxtaposed and in close physical contact with one another and when the two sterile environments are in the undocked position the two door frames are spaced apart from one another and the two doors seal the sterile environments. The two door frames and the doors have a potentially non-sterile peripheral juncture located at the juncture between the doors and door frames when the doors are in a closed position sealing the sterile environments when the sterile environments are in their docked position.