FitEar is known in Japan for making custom IEMs primarily for professional artists, musicians and likewise in the industry. They also have custom IEMs for the standard consumer.
These are FitEar's universal IEMs, TO GO! 334. They are based on their custom IEMs MH334.
3Way / 3Unit / 4 Driver (Balanced Armatures)
Low-1 / Low・Mid-2 / High-1
3.5mm headphone jack