Danco 51880 Trap Vent, Plastic, Black

The Danco trap vent 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 trap vent, 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.