A simple pocket calculator. April wins this in a game of cups in Marcuria, using her magnetised screwdriver. Exactly how the pocket calculator ended up in Marcuria is never explained; the Cups Handler describes it as an artefact from the mysterious world of science but doesn't say where he got it.
Later, April uses it in a challenge against the Alchemist Roper Klacks. When Klacks starts playing with the buttons, he is sucked inside the calculator, suggesting either the calculator itself is magic or this is a side effect of someone with a high magic affinity trying to use it.
Won from the Cups Handler in Marcuria's marketplace.