Fiio ex1ii dynamic iem earphones with aerospace nanotech titanium diaphragm black the ex1 2nd gen earphones have been certified to use the hi res audio logo by the prestigious japan audio society which means that it has passed certain audio quality tests including being able to produce 40khz sound tones with this certification you can be sure that the ex1 2nd gen has a natural cohesive sound that lets you listen to high resolution audio the way it was meant to be listened to the ex1 2nd gen