I received the Duo for Christmas and have gone through 2 of these. The screw grooves for the lock, if damaged at all cause the lid to pop off during brewing and half the pod full of grounds end up in your cup and inside the machine. I also noticed like other reviewers this simply does not fit correctly even when removing the plus adapter and the k-cup holder from the machine. It has a lot of play in between the machine and the filter. I had no issues in my old brewer, worked flawlessly. Very disappointed that it is not as universal as claimed.