Stax

Electrostatic Audio Products

https://staxaudio.com/

From the manufacturer:

STAX was found in 1938. In 1959, STAX developed the world’s first electrostatic headphone and introduced SR-1 in 1960.  Today STAX continues their tradition by offering the finest headphones for both professional and audiophile applications.  STAX refers to all its headphones “EARSPEAKERS”; such Ultra-High Fidelity devices for reproducing music can only be compared with the best cost-no-object loudspeakers, not other headphones.  The term ”EARSPEAKER” is, therefore, more descriptive of STAX’s contribution to today’s most advanced level of sonic transduction.