Ithaili elinomthelela oluphansi olusekelwe ngesikhumba esihlukile (isikhumba somoya) lisekelwe ekhishi le-drill, olwenziwe ngezinhlobo ezinomthelela, ukunakekelwa okusheshayo, nokwenza kube nomthelela oluhle. Kungenzeka ukusetshenziswa ekupheleni kwezinkanyezi zomhlaba nokwenza izinto ezinzima ezinye. Isitshalo sisebenza ngesimo esimbalwa, isilinganiselwe, kanye nokukhanya; Ngokwezimo yezindawo zokulawula, kusebenzisa izindlela zomthelela ezinkulu ezindaweni zangaphandle kanye nezindawo zomthelela ezindaweni zangaphakathi, kwenza ukusebenza kube nokuhamba okuncane. Izindlela zokungena nokuhamba kwamanzi zimelelwe ngokusebenzisa isivikelo esiqondile, ekwenzeni ukuphela kwemvume yamanzi; Isikwele sisebenzisa isenzo yokwenza ngokwekwele okwesikhombisa ukuthi isha ayisakwazi ukwenzeka ngokwezokwenzeka okwesikhombisa, futhi ayikwazi ukuba ibe yinto esheshayo, ekwenzeni ukuphela kwemvume yamanzi.