This part was not included in the drain installation package I ordered for my rectangular Kraus glass vessel sink. When the sink was installed without it, it was wobbly, so I called overstock and they said that this ring is not a required part for the large sinks. So I went ahead and ordered one anyway and glad that I did. It does raise the sink up a little above the countertop, but it is now more stable and I think it makes the sink look better. So, while it's not necessary I would recommend getting one, especially if your sink wobbles.