This seal is also referred to as a door gasket, and it is designed for use on dishwashers. It is installed on the door of the appliance, and it seals the space between the tub of the dishwasher and the door. This seal works for prevent water from escaping during the wash cycle. Over time the seal might wear out, or it might get damaged, when that happens you will start to notice leaks. If water is leaking from the door of your dishwasher during operation it may be time for you to replace the door gasket on your appliance. This door seal is made of rubber, and it is black in color.