I was assured that this product would work with my K-Duo. After hours of struggle, I got it to work "one" time. Taking it out and cleaning presented all sorts of problems when trying to get it back into the system. I have since spent many hours trying to get it to fit back into the system, with no luck. Further, I now can't get the original one cup mechanism back into the system. Don't waste your money. It's not worth the time and effort. I've read the instructions many times. Not a big help. In fairness, I love the K-Duo. It makes a great cup of coffee, but this filter is a disappointment.