The author remixed this model.
The origanl was fantasic but I wasnt a fan of the magnets, so I remixed it to take magnetic tape, that fits more Tonies and you dont have to be as preciese with where you put them.
This is what I used
https://www.amazon.co.uk/GAUDER-3M-Magnetic-Tape/dp/B07FFJCW91/ref=sr_1
But any 15mm X 1.8/2mm should be fine