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