NMR tube holder

This is a holder for NMR (nuclear magnetic resonance) tubes. NMR instruments are usually away in dedicated spaces and user constantly have to transport a few tubes to and from the instrument. Surprisingly, there isn't a commercially available case to safely transport these delicate glass tubes.
This thing is designed for 9x 5mm NMR tubes. The OpenSCAD file is included as well, since I am certain there are a million ways to improve this, so knock yourselves out!

Pending: Inserts for 3mm tubes (should be piece of cake to make, just haven't had time to do it)