HUB

the design of this part is easy to break when closing the top rack.

there is a hub that clicks in place and a spinner within this that makes the water spray evenly on the top of the tub of the dishwasher

the part broke when closing the rack [a dish too tall hit it]

it took less than 5 minutes to replace as the part just clicks into two edge spots i did this without removing the rack or even looking into the tub all by feel