You might be surprised by how much innovation there is in the seemingly simple world of highlighters. It still surprises us, and we're a pen shop, so we should be used to this sort of thing by now. Everyone knows about the classic Stabilo Boss highlighter, but did you know they are refillable? Did you know there's an executive version of the Boss, with rubber grips, and a different ink that's less prone to smudging inkjet print and fountain pen ink?
Other interesting innovations in highlighting technology?