Easy to print, easy to mount printed in 4 parts with pla filament looks very sensitive and strong too just needs a little sanding to make the cylinder smooth inside video here https://youtu.be/nUxBxbF-HGE
needs 2 magnets (8mm) per cylinder https://www.amazon.fr/dp/B07JHQNDZC/ref=pe_3044141_189395771_TE_dp_1 also need a 2mm shaft to make the piston cut 21mm of that shaft https://fr.aliexpress.com/item/4000471083971.html?spm=a2g0s.12269583.0.0.53293ad4oUaikG