OK, so this is undoubtedly the coolest thing I’ve seen this week: The ElectroPen produces a five-millisecond burst of 2,000 volts, whereas a commercial machine can be tuned to different durations and voltages for various applications. But the ElectroPen is much more accessible: anyone can build their own for a few dollars to crack at least one cell type. “There is definitely a need for low-cost entry to be able to have everyone do those experiments,” du Jeu says.