STAX produce exclusively electrostatic headphones, or “earspeakers” as they call them, in Japan, since 1938. STAX chose the electrostatic technology for its ability to produce transparent sound, and low weight for comfort/ergonomics, both due to the driver design not employing fixed magnets and moving coils, as opposed to other common headphone driver designs. The minimal weight of the driver ensures a very quick response to the signal, creating a more faithful sound reproduction.