Either you need a NP Max Adapter or you need to modify the original adapter. As the 3ml cardridges are a little bit wider, you'll need to file down the inside of the original adapter a little to increase the inner diameter. Then you need an additional threaded connector and a spacer/washer.Do standard 3ml cartridges fit in the Novopens?
They are cheaper than Gansulin... I want to buy more pens but Gansulin is about €65 now with the extra import duty.