1.with auto water-pump 2.Small.light,high efficiency, ... clutch, Dimond core drill 1.stable quality and outstanding performance 2.with auto pump for water cooling3.OEM is avaliable Great ... tool which can drill on RC,brick and stone,rock,china and fireproof materials.It is hold such characteristics ... -checking,airfield runway,tunnel of road,railroad and railroad bridge. with auto pump diamond core drill