I have a Green Stuff World hobby paint shaker, very useful tool. Unfortunately the connector between the shaker and the rubber container broke up, and the original spare part seems far from arrive anytime soon. But I have a 3d printer, and a minimum of competence to take measurement for designin a spare part on my own. And here it is, hope it will be useful to someone else.

Printed in GST3D PLA+, but any stiff material will be ok.