This part is a replacement wheel assembly for your lower dishrack. The wheels on the dishrack allow it to roll in and out of the dishwasher efficiently. If one of your wheels is broken or warped, you will need to replace it. Be sure to inspect the dishrack tines that connect to the wheels when making this repair. Occasionally they can become damaged or rusted out, and in this case, you may have to buy a new dishrack. Most lower racks contain 8 individual wheels, but they are sold individually. The wheel is approximately 1.5 inches in diameter and is made of gray plastic.