The MDBHH holds dropper bottles that are approximately 38.80 mm in major diameter. Each holder holds 7 bottles and t slots are included on each flat to allow you to stack as many holders as you want together. 

 I have also included two models for varying tolerances on the t slots. My printer currently over extrudes so my initial model was quite tight, that model is the tight model, I have also loosened up the model slightly to work with my current printer and settings, that is the sloppy model.

The ID for the holes is 39.40 mm and the OD on my bottle is 38.80, for my printer this is a near perfect fit that is easy to take each bottle in and out of but still retains the bottles even if you shake the holder upside down. I have included the F3D files if you wish to change the ID on the model to suit your own printer or bottles.

No supports needed, and this model will work at practically any layer height.