Great find. They look like they would do something similar to spray markers, but a lot lot cheaper. I'll have to get some of these. Course Tria Panatone spray markers come in something like 290 different colors. You would not believe how many different olive greens they have and how many shades of red.
BTW, for anyone interested in the spray markers, they can be found at Currys
, which is the source Chris told me about.