Thrifco 4400891 Kitchen Dishwasher Air Gap Cap - Chrome - Plastic

Air Cap prevents sewage from flowing back into the dishwasher. When water flows through the drain hose, it creates a suction on the water still in the dishwasher. The air gap, makes a hole for air to get in. That way, the water only leaves the dishwasher when it supposed to, when it is pumped out.