ALFI brand AB2609-BN Brushed Nickel Air Gap Cover and Tube for Dishwasher AB2609-BN

The air cap prevents sewer water from flowing back into the dishwasher. As the water flows through the drain hose, it creates a suction on the water that is still in the dishwasher. The air gap provides a hole for air to get in, ensuring that water only leaves the dishwasher when it is pumped out.