Product review (5 stars): Fits perfectly on my KitchenAid dishwasher
As others have mentioned, my drain plug was melted from the lid not being tightened and then it fell out and rested against the heating element.  I ordered this part for my Kitchen Aid dishwasher (model # KUD102FRSS0) and it fits perfectly.  This part DOES contain the rubber O-ring on the top of the lid that seals the lid to the dishwasher door.  I've seen other similar parts reviewed on Amazon where people purchased a similar cap and it did not come with the rubber O-ring.  Very happy with this replacement part.