{TAIL ~ The circuitry} may include a socket for connection to the input/output of {HEAD ~ a device} with which the earphone is to be used, e.g. a mobile phone, portable computing device or personal sound system 
{ TAIL ~ The circuitry } may include a socket for connection to the input / output of { HEAD ~ a device } with which the earphone is to be used , e.g. a mobile phone , portable computing device or personal sound system
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH