Keuring swears that this reusable filter is compatible with the "Duo" model.  They lie.  It will not fit in my new Duo, and the BS explanations they have provided on other 1 star reviews from customers who encountered the same problem are useless and do not work.  A customer should NOT have to call Customer Support to figure out how to get an allegedly compatible accessory to work!  I can't imagine why Keurig would treat their customers this way, but I'll think twice before buying anything else from them!!