a locking mechanism, provided on {HEAD ~ each} of the sockets, for locking the plug body engaged in the associated socket and preventing {TAIL ~ the plug body} from being disengaged in the axial direction thereof, 
a locking mechanism , provided on { HEAD ~ each } of the sockets , for locking the plug body engaged in the associated socket and preventing { TAIL ~ the plug body } from being disengaged in the axial direction thereof ,
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH