What kinds of pens are good for marking tile? Why?

Tile manufacturers and stone fabricators have a particular marking need: a mark that will last the process of these abrasive waterjet machines. They are a big user of "Squeezee" Paint pens. They have determined that the Squeezee markers lay down a thick and durable enough mark to withstand the running water.

The Flomaster Squeezee Paint pen lays down a good bead of paint. Such a dense mark is highly visible on tiles, and stone. Good news for stone fabricators: the wet cutting machines will not wash off the pen mark. Everywhere in the world people use squeeze pens meant to withstand the running water of wet cutters.