The present invention provides {HEAD ~ a cutter} for an earth boring system that has {TAIL ~ a rotary unit} which bores into earth formations to form a hole therein 
The present invention provides { HEAD ~ a cutter } for an earth boring system that has { TAIL ~ a rotary unit } which bores into earth formations to form a hole therein
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH