This part is the replacement carrier roller for your dishwasher. It is also known as the wheel support. It is made of gray plastic and is approximately 5 inches by 2 inches. The carrier roller supports the wheels on your upper dish rack so it can slide in and out of the dishwasher efficiently. This roller is for the right side of the dish rack, the left side is sold separately. Because it is made of plastic, the roller can occasionally crack and break, and when this occurs, it will need to be replaced. If you notice that your dish rack is having difficulty sliding in and out, you should check to see if the roller is damaged. This is an OEM part from the manufacturer and it is sold individually.