THESE BLACK COLOUR PX 100 HEADPHONES ARE RARE AND RATHER WONDERFUL HIGH-END AUDIOPHILE SOUNDING PORTABLE HEADPHONES. HARDLY NO LISTENING FATIGUE. FOR MY OWN PERSONAL USE I HAVE PAIRED WITH A SHANLING M0 PORTABLE (PHOTO FOR ILLUSTRATION PURPOSES AND PLAYER/CDS WHEN TRANSFERRED INTO WAV FILES NOT INCLUDED ) MUSIC PLAYER BRINGS THAT BRINGS OUT THE BEST OUT OF THESE HEADPHONES.
eBay