The PU-10 is for sinks WITHOUT overflows. The PU-11 is for sinks WITH overflows. Although their sizing is similar, you cannot use them interchangeably. You'd have to consider your sink.

Yes. My sink does not have the overflow. The drain popper is fine but the plastic right that goes between the sink and the countertop has broken and it's leaking. That's why I wanted to replace it. So it wouldn't fit in the sink without overflow?

Now I see what you are saying..There's a built in overflow. I see the hole on the popper. I need PU-10 but can't find it. Would I be able to take out the white plastic ring from PU and repair my PU-10 unit? The ring is broken and water is leaking from there.

Unfortunately, I do not have a PU-10 here to examine and answer that question. What you can do, is call KRAUS's technical department department and see if it is possible to replace that plastic part on your existing unit. 1-800-775-0703.

If for whatever reason you need to purchase a new unit, here is our [listing for the PU-10 available in three different finishes.[(https://www.houzz.com/products/pop-up-drain-chrome-prvw-vr~14998779?lid=24124991)