{TAIL ~ A device} for performing electroacoustic functions including noise cancellation, communication interface, and {HEAD ~ headphone functions} 
{ TAIL ~ A device } for performing electroacoustic functions including noise cancellation , communication interface , and { HEAD ~ headphone functions }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD