A cute science pun (chemistry and physics)! A cation is an ion with more protons than elections giving it an overall positive charge. A dication has a +2 positive charge and a trication a +3 positive charge (but they are both cations, they can just be given special names indicating how much extra positive charge they have). Here's some cats and balls of wool to illustrate it :)
Where to buy online
Direct from us here - see products featuring this design.
You can find the design on t-shirts in most stores, but also on other products depending on the store (e.g. hoodies, mugs, stickers, notebooks, phone cases, greeting cards, cushions, socks, face masks etc).