The add-on to the evaporator is used when mixing solutions within the NMR tubes. That is for both the mixing solutions for NMR spectra recording but may be used when one aims at washing NMR tubes and does not want to shake the washing solution manually or when the ultrasound washer is unavailable.
The author remixed this model.
The difference is the material (I used FLex to print it), the shape of the head holding the NMR tubes and the number of tubes to be mixed at a time.