D1 to Uni Power Tank Refill Converter

As Uni-ball discontinue this pen, it becomes very hard to obtain the original refill for it. I made this model to convert the D1 refill into the Power Tank refill shape. I use all default setting on the Bambu lab X1 Carbon with 0.4mm nozzle and their own PLA basic filament. 

Since the spring will not work with the D1 refill, I had made the fit quite tight, so the refill will not fall out. If you want it to be loser, I suggest to use 0.16mm layer high and higher quality settings. As for me, all default work just fine.

I am very new to 3d modelling, so if you have any better designs, feel free to remix it.