The gasket insert is connected to the gasket in the bottom of your dishwasher door. It is a small piece of white plastic that measures approximately 4 inches by 1 inch, and is sold individually. The gasket insert helps the gasket create a seal on the door, so water doesn’t leak out when the dishwasher is running. If your dishwasher is leaking, check to see if the gasket insert is damaged. If the insert is damaged, you will need to replace it. The problem may be with the gasket itself, in which case you may need to replace that part as well.