An instrument is provided for {HEAD ~ working} of surfaces of parts inside engineered cavities by {TAIL ~ means} of a tool, with the possibility of simultaneous viewing of the site of the working operation 
An instrument is provided for { HEAD ~ working } of surfaces of parts inside engineered cavities by { TAIL ~ means } of a tool , with the possibility of simultaneous viewing of the site of the working operation
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH