No Moomin mugs are the exact same size. This model is small enough to work as a universal stacker, allowing them to fit any cup. This makes the stackers able to move a bit around in bigger mugs of 30Cl. They do fit the bigger mugs without issue, but if you would like a snugger fit, for mugs with an inner diameter of about 7.7 cm I recommend scaling it up to about 104% size, and for 7.8 cm I recommend about 105% size. Any smaller, I generally recommend the original models. Linear supports is what has worked the best for me.