Suw yuav muab tag nrho cov hnav tiv thaiv rau excavator thoob, suav nrog bimetallic coj tuav, chocky tuav, hnav khawm thiab hnav cov ces kaum, hnav daim di ncauj. Lub thoob yuav tau txais kev tiv thaiv tag nrho thiab zoo heev thiab kev pab cuam lub neej yog multiplied serval lub sij hawm.

Thov hu rau peb kom paub meej ntxiv yog tias xav tau.